; and (B) in paragraph (2)— (i) in subparagraph (B), in the matter preceding clause (i), by striking 500 grams and inserting 400 grams ; (ii) in subparagraph (C), by striking 28 grams and inserting 160 grams ; and (iii) in subparagraph (H), by striking the period at the end and inserting a semicolon. (b) Attorney General certification (1) In general For a defendant sentenced before the date of enactment of this Act, the Attorney General shall submit to the court that sentenced the defendant a certification regarding whether, in the opinion of the Attorney General, the sentence of the defendant should be reduced, as if the amendments made by subsection (a) were in effect at the time the offense was committed. In making a certification under this paragraph, the Attorney General shall consider the factors in section 3553(a) of title 18, United States Code. (2) Resentencing If the Attorney General submits a certification under paragraph (1) indicating that, in the opinion of the Attorney General, the sentence of the defendant should be reduced, as if the amendments made by subsection (a) were in effect at the time the offense was committed, the court that imposed the sentence of the defendant may impose such a reduced sentence. 3. Federal research (a) In general Not later than 1 year after the date of enactment of this Act, the Attorney General, in coordination with the Administrator of the Drug Enforcement Administration and the Secretary of Health and Human Services, shall review and submit to the Committee on the Judiciary and the Committee on Health, Education, Labor, and Pensions of the Senate and the Committee on the Judiciary and the Committee on Energy and Commerce of the House of Representatives a report on— (1) the average individual dosage amount of both powder cocaine and cocaine base; (2) the lethality of both powder cocaine and cocaine base as measured by individual dosage