Bar Exam prep question - see description

Question

An attorney represented a client in an action against the cli-ent’s former business partner to recover damages for breach of contract. During the representation, the client presented the attorney with incontrovertible proof that the partner had committed perjury in a prior action that was resolved in the partner’s favor. Neither the attorney nor the client was involved in any way in the prior action. The attorney believes that it would be detrimental to the client’s best interests to reveal the perjury because implications might be drawn from the former close personal and business relationship between the client and the partner. Is it proper for the attorney to disclose the perjury to the tribunal?

Answer 1

Yes, as evidence to impeach the former partner’s credibility