Which of the following can be used to challenge a witness's credibility?

Prior inconsistent statements can be used to challenge a witness's credibility because they demonstrate that the witness has previously made statements that contradict their current testimony. This inconsistency suggests that the witness may not be reliable or truthful, as it raises questions about their memory or honesty. Courts typically allow this type of evidence for attacking credibility since it directly addresses the trustworthiness of the witness's testimony.

Other options, while they may provide information or context, do not directly undermine a witness's credibility in the same manner. For instance, testimony from another witness might offer support or alternative accounts of events, but it doesn't necessarily discredit the original witness. Affidavits can provide statements or assertions but are not typically used in the same way to challenge credibility directly during testimony. Character references can portray the witness in a positive or negative light, but they do not address inconsistencies in the witness's own statements, which is critical for evaluating credibility in legal settings.