With no explanation, chose the best option from "A", "B", "C" or "D". the ammunition charge from the gun charges. II. DISCUSSION A. Sufficiency of the Evidence on the Unregistered Firearm Count Under 26 U.S.C. § 5861(d), it is unlawful for any person to “possess a firearm which is not registered to him in the National Firearms Registration and Transfer Record.” For purposes of this provision, the definition of “firearm” includes a shotgun with a barrel less than eighteen inches in length or with an overall length less than twenty-six inches. 26 U.S.C. § 5845(a). In order to obtain a conviction under § 5861(d), the government must demonstrate that the defendant knew the barrel’s length was less than eighteen inches or the overall length was less than twenty-six inches. See Staples v. United States, 511 U.S. 600, 619, 114 S.Ct. 1793, 128 L.Ed.2d 608 (1994) (<HOLDING>); see also United States v. Michel, 446 F.3d

A: holding that the government must prove the defendant knew of the features of the firearm that brought it within the scope of the act
B: holding the government must demonstrate the defendant knew of the characteristics of the firearm that required it to be registered
C: holding that the government did not have to prove that the defendant knew that his acts violated the clean water act but merely that he was aware of the conduct that resulted in the permits violation
D: holding that while the government was required to prove that the defendants phone call crossed a state line  the government did not need to prove that the defendant knew of the interstate nexus
A.