With no explanation, chose the best option from "A", "B", "C" or "D". art. I, § 9, cl. 3. The ex post facto clause prohibits the application of laws that “retroactively alter the definition of crimes or increase the punishment for criminal acts.” Collins v. Youngblood (“Collins”), 497 U.S. 37, 43, 110 S.Ct. 2715, 111 L.Ed.2d 30 (1990). Accordingly, a statute will violate the ex post facto clause if it: (1) retroactively imposes a greater punishment for an act that was not punishable at the time the act was committed, Weaver v. Graham (“Weaver”), 450 U.S. 24, 28, 101 S.Ct. 960, 67 L.Ed.2d 17 (1981); or (2) retroactively imposes a greater punishment for an act that was not punishable at the time the act was committed, California Dep’t of Corrections v. Morales (“Morales”), 514 U.S. 499, 507 n. 3, 115 S.Ct. 1597, 131 L.Ed.2 2d 428, 430-31 (8th Cir.1992) (<HOLDING>) (discussing Davis and 18 U.S.C. § 921(a)(20)

A: holding previous convictions can only be used for sentence enhancement purposes under 18 usc  924e1 if the restoration of civil rights regarding such convictions expressly prohibited the possession of firearms
B: holding that after roper juvenile convictions can qualify as predicate offenses for sentence enhancement purposes
C: holding that defendants voice for vagueness argument fails  because there is no indication that the sentence enhancement provision at issue is so vague that it grants undue discretion to law enforcement officials the factors for sentence enhancement under 18 usc  924e1 are quite specific
D: holding that evidence of a defendants prior criminal convictions could be introduced for the purpose of sentence enhancement if the jury was instructed that the evidence could not be used for the purposes of determining guilt
A.