of credit refundable 40 percent of the credit allowable under subsection (a)(1) (determined without regard to this subsection and section 26(a) and after application of all other provisions of this section) shall be treated as a credit allowable under subpart C (and not under this part). The preceding sentence shall not apply to any taxpayer for any taxable year if such taxpayer is a child to whom section 1(d) applies for such taxable year. (c) Limitation based on modified adjusted gross income (1) In general The amount allowable as a credit under subsection (a) for any taxable year shall be reduced (but not below zero) by an amount which bears the same ratio to the amount so allowable (determined without regard to this subsection and subsection (b) but after application of all other provisions of this section) as— (A) the excess of— (i) the taxpayer’s modified adjusted gross income for such taxable year, over (ii) $80,000 (twice such amount in the case of a joint return), bears to (B) $10,000 (twice such amount in the case of a joint return). (2) Modified adjusted gross income For purposes of this subsection, the term modified adjusted gross income means the adjusted gross income of the taxpayer for the taxable year increased by any amount excluded from gross income under section 911, 931, or 933. (d) Other limitations (1) Credit allowed only for 5 taxable years An election to have this section apply may not be made for any taxable year if such an election (by the taxpayer or any other individual) is in effect with respect to such student for any 5 prior taxable years. (2) Credit allowed only for first 5 years of postsecondary education (A) In general No credit shall be allowed under subsection (a) for a taxable year with respect to the qualified tuition and related expenses of an eligible student if the student has completed (before the beginning of such taxable year) the first 5 years of postsecondary education at an eligible educational institution. (B) Fifth year limitations In the case of an eligible