(a) A participant may elect to receive the participant's share of the individual account in a

(1) lump sum payment, which is a single payment of the entire balance in the account;

(2) periodic lump sum payment, which is a payment of a portion of the balance in the account, not more than twice each year;

(3) period certain annuity payment, which is an annuity payable in a fixed number of monthly installments for a duration of 60, 120, or 180 months;

(4) life annuity with a period certain payment, which is an annuity payable until the later of the first day of the month in which the annuitant's death occurs, or the date on which the payment of a fixed number of monthly installments is completed; the period certain for installments is 120 or 180 months;

(5) single life annuity payment, which is an annuity payable monthly until the first of the month in which the annuitant's death occurs;

(6) joint and survivor annuity payment, which is an annuity payable monthly to the member until the first of the month in which the member's death occurs; after the member's death, a survivor annuity equal to 50 percent or 100 percent of the member's benefit, as previously elected by the member, shall be paid monthly to the joint annuitant for the remainder of the survivor's lifetime; or

(7) payment as authorized by a regulation adopted by the commissioner of administration.

(b) Upon the death of an annuitant whose payments have commenced, an annuitant's beneficiary shall receive further payments only to the extent provided in accordance with the form of payment that was being made to the annuitant. The remaining portion of the interest shall continue to be distributed at least as rapidly as under the method of distribution being used before the annuitant's death.

(c) If a participant dies before the distribution commencement date, distribution of the participant's entire interest to a beneficiary shall be payable in any form other than a joint and survivor annuity.

(d) If an unmarried member or other participant fails to elect a form of payment before the distribution commencement date, the account shall be paid to a beneficiary in the form of a lump sum to the extent required by the minimum distribution requirements set out in the Internal Revenue Code. If a married member fails to elect a form of payment before the distribution commencement date, the account shall be paid in the form of a 50 percent joint and survivor annuity, with the member's spouse as the joint annuitant.