imposed by section 26(a) for such taxable year reduced by the sum of the credits allowable under subpart A (other than this section and sections 23, 25 and 25D), such excess shall be carried to the succeeding taxable year and added to the credit allowable under subsection (a) for such taxable year (and treated as attributable to a qualified contribution which is not made in connection with a trade or business). (ii) Limitation No credit may be carried forward under this subparagraph to any taxable year following the fifth taxable year after the taxable year in which the credit arose. For purposes of the preceding sentence, credits shall be treated as used on a first-in first-out basis. (e) Election (1) In general This section shall apply to a taxpayer for a taxable year only if such taxpayer elects to have this section apply for such taxable year. (2) No double benefit In the case of any taxpayer who has made an election under paragraph (1), any qualified contribution shall not be taken into account in determining the amount of any other credit or deduction under this chapter. . (b) Conforming amendments Section 38(b) of such Code is amended by striking plus at the end of paragraph (40), by striking the period at the end of paragraph (41) and inserting , plus , and by adding at the end the following new paragraph: (42) the portion of the qualifying pregnancy center credit to which section 30E(d)(1) applies. . (c) Clerical amendment The table of sections for subpart B of part IV of subchapter A of chapter 1 of the Internal Revenue Code of 1986 is amended by inserting after the item relating to section 30D the following new item: Sec. 30E. Contributions to qualifying pregnancy centers. . (d) Effective date The amendments made by this section shall apply to contributions made in taxable years beginning after the date of the enactment of this Act.