(b) Prior mortgages on real property. The lien under subsection (a) of this section shall be subject to the lien of any mortgage indebtedness on real property incurred in good faith prior to the time when the tax under this article became a lien. Such real property may be sold and conveyed free from any such tax lien in an action to foreclose such mortgage to which the people of the state of New York shall have been made a party defendant by reason of the existence of the lien for the tax. The lien may then attach to any surplus moneys which result from such sale, to be determined in the proceedings for the distribution of such surplus moneys.

(c) Discharge of lien.--Subject to such rules or regulations as the commissioner may prescribe, the commissioner may issue a certificate of discharge of any or all of the property subject to the lien imposed by this section if he or she finds that the liability secured by such lien has been fully satisfied or provided for, upon application for such discharge. A certificate of discharge issued under this subsection shall be held conclusive that the lien upon the property covered by the certificate is extinguished.

(d) Recording of certificate of discharge. A certificate of discharge issued under subsection (c) of this section may be recorded in the office of the recording officer of the county where real property described therein is situated.

(e) Power of executor to sell. The executor shall have full power to sell so much of the property of the estate as will enable him to pay the tax imposed by this article in the same manner that he is permitted by law to do for payment of debts of the estate.