2020 . (2) Effective date The amendments made by this subsection shall apply to fuel sold or used after December 31, 2017. (f) Credit for biodiesel and alternative fuel mixtures (1) In general Section 6426 is amended— (A) in subsection (c)(6), by striking 2017 and inserting 2020 , (B) in subsection (d)— (i) in paragraph (2)(D), by striking liquefied , and (ii) in paragraph (5), by striking 2017 and inserting 2020 , and (C) in subsection (e), by amending paragraph (3) to read as follows: (3) Termination This subsection shall not apply to any sale or use for any period after— (A) in the case of any alternative fuel mixture sold or used by the taxpayer for the purposes described in subsection (d)(1), December 31, 2020, (B) in the case of any sale or use involving hydrogen that is not for the purposes described in subsection (d)(1), December 31, 2020, and (C) in the case of any sale or use not described in subparagraph (A) or (B), December 31, 2017. . (2) Clarification of rules regarding alternative fuel mixture credit Paragraph (2) of section 6426(e) of the Internal Revenue Code of 1986 is amended by striking mixture of alternative fuel and inserting mixture of alternative fuel (other than a fuel described in subparagraph (A), (C), or (F) of subsection (d)(2)) . (3) Effective date (A) In general The amendments made by paragraph (1) shall apply to fuel sold or used after December 31, 2017. (B) Clarification of rules regarding alternative fuel mixture credit The amendment made by paragraph (2) shall apply to— (i) fuel sold or used on or after the date of the enactment of this Act, and (ii) fuel sold or used before such date of enactment, but only to the extent that credits and claims of credit under section 6426(e) of the Internal Revenue Code of 1986 with respect to such sale or use have not been paid or allowed as of such date. (4) Special rule for certain periods Notwithstanding any other provision of law, in the case of— (A) any biodiesel mixture credit properly determined under section 6426(c) of the Internal