(a) For a class A felony, the term shall be life imprisonment;

(b) For a class B felony, the term shall be fixed by the court, and shall not exceed twenty-five years;

(c) For a class C felony, the term shall be fixed by the court, and shall not exceed fifteen years;

(d) For a class D felony, the term shall be fixed by the court, and shall not exceed seven years; and

(e) For a class E felony, the term shall be fixed by the court, and shall not exceed four years. 3. Minimum period of imprisonment. The minimum period of imprisonment under an indeterminate sentence shall be at least one year and shall be fixed as follows:

(a) In the case of a class A felony, the minimum period shall be fixed by the court and specified in the sentence.

(i) For a class A-I felony, such minimum period shall not be less than fifteen years nor more than twenty-five years; provided, however, that (A) where a sentence, other than a sentence of death or life imprisonment without parole, is imposed upon a defendant convicted of murder in the first degree as defined in section 125.27 of this chapter such minimum period shall be not less than twenty years nor more than twenty-five years, and, (B) where a sentence is imposed upon a defendant convicted of murder in the second degree as defined in subdivision five of section 125.25 of this chapter or convicted of aggravated murder as defined in section 125.26 of this chapter, the sentence shall be life imprisonment without parole, and, (C) where a sentence is imposed upon a defendant convicted of attempted murder in the first degree as defined in article one hundred ten of this chapter and subparagraph (i), (ii) or (iii) of paragraph (a) of subdivision one and paragraph (b) of subdivision one of section 125.27 of this chapter or attempted aggravated murder as defined in article one hundred ten of this chapter and section 125.26 of this chapter such minimum period shall be not less than twenty years nor more than forty years.

(ii) For a class A-II felony, such minimum period shall not be less than three years nor more than eight years four months, except that for the class A-II felony of predatory sexual assault as defined in section 130.95 of this chapter or the class A-II felony of predatory sexual assault against a child as defined in section 130.96 of this chapter, such minimum period shall be not less than ten years nor more than twenty-five years.

(b) For any other felony, the minimum period shall be fixed by the court and specified in the sentence and shall be not less than one year nor more than one-third of the maximum term imposed. 4. Alternative definite sentence for class D and E felonies. When a person, other than a second or persistent felony offender, is sentenced for a class D or class E felony, and the court, having regard to the nature and circumstances of the crime and to the history and character of the defendant, is of the opinion that a sentence of imprisonment is necessary but that it would be unduly harsh to impose an indeterminate or determinate sentence, the court may impose a definite sentence of imprisonment and fix a term of one year or less. 5. Life imprisonment without parole. Notwithstanding any other provision of law, a defendant sentenced to life imprisonment without parole shall not be or become eligible for parole or conditional release. For purposes of commitment and custody, other than parole and conditional release, such sentence shall be deemed to be an indeterminate sentence. A defendant may be sentenced to life imprisonment without parole upon conviction for the crime of murder in the first degree as defined in section 125.27 of this chapter and in accordance with the procedures provided by law for imposing a sentence for such crime. A defendant who was eighteen years of age or older at the time of the commission of the crime must be sentenced to life imprisonment without parole upon conviction for the crime of terrorism as defined in section 490.25 of this chapter, where the specified offense the defendant committed is a class A-I felony; the crime of criminal possession of a chemical weapon or biological weapon in the first degree as defined in section 490.45 of this chapter; or the crime of criminal use of a chemical weapon or biological weapon in the first degree as defined in section 490.55 of this chapter; provided, however, that nothing in this subdivision shall preclude or prevent a sentence of death when the defendant is also convicted of the crime of murder in the first degree as defined in section 125.27 of this chapter. A defendant who was seventeen years of age or younger at the time of the commission of the crime may be sentenced, in accordance with law, to the applicable indeterminate sentence with a maximum term of life imprisonment. A defendant must be sentenced to life imprisonment without parole upon conviction for the crime of murder in the second degree as defined in subdivision five of section 125.25 of this chapter or for the crime of aggravated murder as defined in subdivision one of section 125.26 of this chapter. A defendant may be sentenced to life imprisonment without parole upon conviction for the crime of aggravated murder as defined in subdivision two of section 125.26 of this chapter. * 6. Determinate sentence. Except as provided in subdivision four of this section and subdivisions two and four of section 70.02, when a person is sentenced as a violent felony offender pursuant to section 70.02 or as a second violent felony offender pursuant to section 70.04 or as a second felony offender on a conviction for a violent felony offense pursuant to section 70.06, the court must impose a determinate sentence of imprisonment in accordance with the provisions of such sections and such sentence shall include, as a part thereof, a period of post-release supervision in accordance with section 70.45. * NB Repealed September 1, 2020