(7) Election with respect to life estate for surviving spouse (A) In general In the case of qualified terminable interest property— (i) for purposes of subsection (a), such property shall be treated as passing to the surviving spouse, and (ii) for purposes of paragraph (1)(A), no part of such property shall be treated as passing to any person other than the surviving spouse. (B) Qualified terminable interest property defined For purposes of this paragraph— (i) In general The term “qualified terminable interest property” means property— (I) which passes from the decedent, (II) in which the surviving spouse has a qualifying income interest for life, and (III) to which an election under this paragraph applies. (ii) Qualifying income interest for life The surviving spouse has a qualifying income interest for life if— (I) the surviving spouse is entitled to all the income from the property, payable annually or at more frequent intervals, or has a usufruct interest for life in the property, and (II) no person has a power to appoint any part of the property to any person other than the surviving spouse. Subclause (II) shall not apply to a power exercisable only at or after the death of the surviving spouse. To the extent provided in regulations, an annuity shall be treated in a manner similar to an income interest in property (regardless of whether the property from which the annuity is payable can be separately identified). (iii) Property includes interest therein The term “property” includes an interest in property. (iv) Specific portion treated as separate property A specific portion of property shall be treated as separate property. (v) Election An election under this paragraph with respect to any property shall be made by the executor on the return of tax imposed by section 2001. Such an election, once made, shall be irrevocable. (C) Treatment of survivor annuities In the case of an annuity included in the gross estate of the decedent under section 2039 (or, in the case of an interest in an annuity arising under the community property laws of a State, included in the gross estate of the decedent under section 2033) where only the surviving spouse has the right to receive payments before the death of such surviving spouse— (i) the interest of such surviving spouse shall be treated as a qualifying income interest for life, and (ii) the executor shall be treated as having made an election under this subsection with respect to such annuity unless the executor otherwise elects on the return of tax imposed by section 2001. An election under clause (ii), once made, shall be irrevocable.