Section 108(a)(1)(E) is amended by striking January 1, 2018 each place it appears and inserting January 1, 2021 . (b) Conforming amendment Section 108(h)(2) is amended by inserting and determined without regard to the substitution described in section 163(h)(3)(F)(i)(II) after clause (ii) thereof . (c) Effective date The amendments made by this section shall apply to discharges of indebtedness after December 31, 2017. 102. Treatment of mortgage insurance premiums as qualified residence interest (a) In general Section 163(h)(3)(E)(iv)(I) is amended by striking December 31, 2017 and inserting December 31, 2020 . (b) Effective date The amendment made by this section shall apply to amounts paid or incurred after December 31, 2017. 103. Reduction in medical expense deduction floor (a) In general Section 213(f) is amended to read as follows: (f) Temporary special rule In the case of taxable years beginning before January 1, 2021, subsection (a) shall be applied with respect to a taxpayer by substituting 7.5 percent for 10 percent . . (b) Alternative minimum tax Section 56(b)(1) is amended by striking subparagraph (B) and by redesignating subparagraphs (C), (D), (E), and (F), as subparagraphs (B), (C), (D), and (E), respectively. (c) Effective date The amendments made by this section shall apply to taxable years ending after December 31, 2018. 104. Deduction of qualified tuition and related expenses (a) In general Section 222(e) is amended by striking December 31, 2017 and inserting December 31, 2020 . (b) Effective date The amendment made by this section shall apply to taxable years beginning after December 31, 2017. 105. Black lung disability trust fund excise tax (a) In general Section 4121(e)(2)(A) is amended by striking December 31, 2018 and inserting December 31, 2020 . (b) Effective date The amendment made by this section shall apply on and after the first day of the first calendar month beginning after the date of the enactment of this Act. B Incentives for Employment, Economic Growth, and Community Development