(a) Except as provided in subsection (c) of this section, if the property or interest has devolved to the disclaimant under a testamentary instrument or by the laws of intestacy, the disclaimer shall be filed, as to a present interest, not later than nine months after the death of the deceased owner or deceased donee of a power of appointment and, if of a future interest, not later than nine months after the event determining that the taker of the property or interest has become finally ascertained and his interest is indefeasibly vested. The disclaimer shall be filed in the probate court of the county in which proceedings for the administration of the estate of the deceased owner or deceased donee of the power have been commenced or, if they have not been commenced, in which they could be commenced. A copy of the disclaimer shall be delivered in person or mailed by registered or certified mail to any personal representative or other fiduciary of the decedent or donee of the power.

(b) Except as provided in subsection (c) of this section, if the property or interest has devolved to the disclaimant under a nontestamentary instrument or contract, the disclaimer shall be delivered or filed, as to a present interest, not later than nine months after the effective date of the nontestamentary instrument or contract and, as to a future interest, not later than nine months after the event determining that the taker of the property or interest has become finally ascertained and his interest is indefeasibly vested. If the person entitled to disclaim does not have actual knowledge of the existence of the interest, the disclaimer shall be delivered or filed not later than nine months after he has actual knowledge of the existence of the interest. The effective date of a revocable instrument or contract is the date on which the maker no longer has power to revoke it or to transfer to himself or another the entire legal and equitable ownership of the interest. The disclaimer or a copy thereof shall be delivered in person or mailed by registered or certified mail to the trustee or other person who has legal title to, or possession of, the interest disclaimed.

(c) In any case, as to a transfer creating an interest in the disclaimant made after December 31, 1976, and subject to tax under chapter 11, 12, or 13 of the Internal Revenue Code of 1954, as amended, a disclaimer intended as a qualified disclaimer thereunder must specifically so state and must be delivered not later than nine months after the later of the date the transfer is made or the day on which the person disclaiming attains age 21.

(d) If real property or an interest therein is disclaimed, a copy of the disclaimer instrument may be filed for record in the office of the probate judge of the county in which the property or interest disclaimed is located.