(a) A lifetime transfer to a beneficiary of property that is the subject of a specific testamentary gift is treated as a satisfaction if it is shown pursuant to the provisions of subsection (c) of this Code section that the transfer is intended to satisfy the testamentary gift.

(b) A lifetime transfer of money or other property to a prospective heir or to the beneficiary of a demonstrative, general, or residuary testamentary gift is treated as an advancement if it is shown pursuant to the provisions of subsection (c) of this Code section that the transfer is intended to be a part of the share that the heir would inherit by intestacy or the beneficiary would take under the transferor's will.

(c) The intent to treat a lifetime transfer as a satisfaction or an advancement is shown only if the will provides for the deduction of the lifetime transfer or its value or if the satisfaction or advancement is declared in a writing signed by the transferor within 30 days of making the transfer or acknowledged in a writing signed by the recipient at any time.