With no explanation, chose the best option from "A", "B", "C" or "D". that failure to do so would result in revocation. In United States v. Salas-Camacho, 859 F.2d 788 (9th Cir.1988), this court held that a false statement remains material when a declarant recants it only after he is confronted with suspicion on the part of a government agent and is faced with an imminent inspection that would reveal the truth. Id. at 791-92. Bound by that precedent, we affirm Johnson’s conviction on Count Five. For similar reasons, we hold that the jury instructions regarding Count Five adequately reflected the law as set forth in Salas-Camacho and, therefore, were not erroneous. The prosecutor’s statements in closing argument regarding the officers’ lack of motivation to lie constituted improper vouching. See United States v. Combs, 379 F.3d 564, 574-76 (9th Cir.2004) (<HOLDING>). However, we conclude that in this case such

A: holding that prosecutors remark vouching for credibility of government agent was certainly improper
B: holding that while not reversible error a prosecutors vouching for a witness was improper and should be avoided on retrial
C: holding that a prosecutors argument about the special agents disincentive to lie was impermissible vouching
D: holding that the prosecutors question to the defendant about a prior unrelated offense was improper
C.