(ii) $75,000 in the case of an individual who is not married, and (iii) $55,000 in the case of a married individual filing a separate return. (B) Marital status For purposes of this paragraph, marital status shall be determined under section 7703. (3) Applicable amount For purposes of paragraph (1), the term applicable amount means an amount equal to the quotient of— (A) the amount of the credit allowable under subsection (a), as determined without regard to this subsection, divided by (B) an amount equal to the product of— (i) $20, multiplied by (ii) the total number of qualifying children of the taxpayer. (c) Qualifying child (1) In general In this section, the term qualifying child means a qualifying child of the taxpayer (as defined in section 152(c)) who has not attained 19 years of age. (2) Exception for certain non-citizens The term qualifying child shall not include any individual who would not be a dependent if subparagraph (A) of section 152(b)(3) were applied without regard to all that follows resident of the United States . (d) Inflation adjustment (1) In general In the case of any taxable year beginning after 2017, the $3,000 amount in subsection (a)(1) shall be increased by an amount equal to— (A) such dollar amount, multiplied by (B) the cost of living adjustment determined under section 1(f)(3) for the calendar year in which the taxable year begins determined by substituting calendar year 2016 for calendar year 1992 in subparagraph (B) thereof. (2) Rounding If any increase determined under paragraph (1) is not a multiple of $50, such increase shall be rounded to the nearest multiple of $50. (e) Identification requirements (1) Qualifying child identification requirement No credit shall be allowed under this section to a taxpayer with respect to any qualifying child unless the taxpayer includes the name and taxpayer identification number of such qualifying child on the return of tax for the taxable year and such taxpayer identification number was issued on or before the due date for filing such