taxpayer for any taxable year is the least of— (A) the amount specified in the election made under this subsection, (B) the credit determined under subsection (a) for the taxable year (determined before the application of this subsection), or (C) in the case of a qualified small business other than a partnership or S corporation, the amount of the business credit carryforward under section 39 carried from the taxable year (determined before the application of this subsection to the taxable year). (3) Election (A) In general Any election under this subsection for any taxable year— (i) shall specify the amount of the credit to which such election applies, (ii) shall be made on or before the due date (including extensions) of— (I) in the case of a partnership, the return required to be filed under section 6031, (II) in the case of an S corporation, the return required to be filed under section 6037, and (III) in the case of any other taxpayer, the return of tax for the taxable year, and (iii) may be revoked only with the consent of the Secretary. (B) Limitations (i) Amount The amount specified in any election made under this subsection shall not exceed $250,000. (ii) Number of taxable years A person may not make an election under this subsection if such person (or any other person treated as a single taxpayer with such person under paragraph (5)(A)) has made an election under this subsection for five or more preceding taxable years. (C) Special rule for partnerships and S corporations In the case of a partnership or S corporation, the election made under this subsection shall be made at the entity level. (4) Aggregation rules (A) In general Except as provided in subparagraph (B)— (i) all members of the same controlled group of corporations shall be treated as a single taxpayer, and (ii) all trades or businesses (whether or not incorporated) which are under common control shall be treated as a single taxpayer. (B) Special rules For purposes of this subsection and section 3111(g)— (i) each of the persons treated as a