The trick to answering this question is in demonstrating above average communication skills, such as active listening, mirroring, and effectively communicating non-defensively. A situation like this is nuanced. On one hand, you don't want to deflect blame. Doing so could indicate an unwillingness to accept responsibility for your own actions.

"Someone once blamed me for a mistake made based on a poorly formed assumption. I listened to the information they presented to me. I mirrored them and showed concern for the mistake made and the implications it had on the business. They asked me if I had any questions about the verbal warning they gave me. I followed up by asking them what led them to believe the responsibility for this mistake was mine? They explained their logic, and I corrected them and explained I had nothing to do with this mistake. They showed me why they believed I was the culprit. Explained that wasn't the case and helped them conduct a little research, proving my innocence. We were able to uncover the real culprit, and it turned out the mistake was made by the very supervisor who was trying to give me feedback for the mistake they themself made. This was a little embarrassing for them, I think. Luckily, we never had another conversation like it."