the Secretary shall prescribe) and shall be in such form and manner as the Secretary may prescribe, and (ii) shall apply to such first taxable year and all subsequent taxable years until the first taxable year for which the taxpayer is again treated as an applicable taxpayer by reason of meeting the requirements of paragraph (1)(A). (5) Special rules for married individuals (A) Applicable taxpayers becoming married individuals If an individual was an applicable taxpayer for the taxable year before the individual became a married individual (within the meaning of section 7703), such individual and the individual's spouse shall be treated as applicable taxpayers for such taxable year of marriage and subsequent taxable years until such status is otherwise terminated under this section. (B) Married individuals filing separately If a married individual filing separately is treated as an applicable taxpayer for any taxable year, such individual's spouse shall be treated as an applicable taxpayer for such taxable year. (C) First-year elections Under rules prescribed by the Secretary, if an individual is first treated as an applicable taxpayer for a taxable year by reason of the application of subparagraph (A) or (B), section 496 shall apply to such taxpayer for such first taxable year only with respect to assets held separately by such individual unless such taxable year is also the first taxable year for which the individual's spouse is an applicable taxpayer. (6) Regulatory authority The Secretary shall prescribe such regulations and guidance as may be necessary to carry out the provisions of this subsection, including— (A) rules waiving the application of paragraph (5)(B) in cases where the Secretary determines equitable relief is appropriate, (B) rules providing for the application of this subsection in cases where the filing status of a taxpayer changes between any taxable year and any of the 3 immediately preceding taxable years, including the first taxable year in which a taxpayer files a joint return after