CWanamaker appears correct when he said "Sometimes its best to not say anything at all."
But no answer is not acceptable in a legal situation, that's why all those indicted in front of a congressional hearing say "I do not recall". Sometimes it's best to appear stupid to avoid lying or being hated. But saying "I do not recall" when you do is a lie.
A lie of ommision yes, but not an active fairy tale. but then again I would lie without guilt if someone's life was in danger. Lying to a criminal who is robbing a person - hell yeah!