With no explanation, chose the best option from "A", "B", "C" or "D". clause [of § 921(a)(20) ] defines the rule for determining ‘what constitutes a conviction.’ ... The exemption clause ... is thus just one step in determining whether something should ‘be considered a conviction.’ ”); cf. United States v. Kahoe, 134 F.3d 1230, 1233-34 (4th Cir.1998) (“The plain language of § 921(a)(20) means that a conviction that has been set aside can no longer be disabling. The language does not provide that such a conviction was not disabling between the time it was obtained and the time it was set aside.... Neither the amended language of § 921(a)(20) nor the legislative history of the amendment counsels a result contrary to that set forth in Lewis, and we determine that Lewis is controlling.”); United States v. Thompson, 117 F.3d 1033, 1034 (7th Cir.1997) (<HOLDING>) Like the substantive criminal statutes to

A: holding the use of a 1951 felony conviction as a predicate for a violation of 18 usc  922g1 did not violate the ex post facto clause because the crime of being a felon in possession of a firearm was not committed until after the effective date of the statute under which he was convicted
B: holding that in determining whether a prior conviction is a violent felony a court generally must look only to the fact of conviction and the statutory definition of the prior offense
C: holding that prior indiana felony was conviction for purposes of defendants  922g1 prosecution and noting that although state law determines whether there is a predicate statelaw conviction once the conviction is established federal law dictates that the convicted felon may not possess any firearm
D: holding that a prior conviction obtained in violation of a defendants constitutional rights cannot be used as the underlying conviction in a prosecution under colorados felon with a gun statute
C.