With no explanation, chose the best option from "A", "B", "C" or "D". in choosing between these versions think carefully about what the police could have done if these men, Steven Cross, Detective Lauro, Detective Gerstmeyer, Detective Mansolillo had been people who would deliberately come in here and tell you the truth. Yes, you will hear undoubtedly in summation that Detective Mansolillo made a mistake in the Grand Jury. People make mistakes, and he corrected it here. All right. Defendant did not object to what he now attacks as witness vouching, and so our review in this context is for plain error. United States v. Grabiec, 96 F.3d 549, 550 (1st Cir.1996); United States v. Sepulveda, 15 F.3d 1161, 1187-88 (1st Cir.1993). These first two comments do not, we think, amount to improper vouching. United States v. Cruz-Kuilan, 75 F.3d 59, 62 (1st Cir.1996) (<HOLDING>). The last statement is simply too garbled to

A: holding jury is sole judge of witness credibility and may believe some witnesses and refuse to believe others
B: holding the prosecutor is required to present exculpatory evidence to the grand jury
C: holding that it is not vouching for prosecutor to say that jury should come to believe on the evidence that the events occurred the way the governments witnesses said they did
D: holding that a prosecutor may comment on the absence of evidence so long as there is sufficient evidence to support the prosecutors version of events
C.