base amount
(1) Base amount The term “base amount” means— (A) except as otherwise provided in this paragraph, $25,000, (B) $32,000 in the case of a joint return, and (C) zero in the case of a taxpayer who— (i) is married as of the close of the taxable year (within the meaning of section 7703 ) but does not file a joint return for such year, and (ii) does not live apart from his spouse at all times during the taxable year.