public speaking/presentation

My presentation was good.At the end of it,studends ask question about that specific topic n u have to answer them.I said loudly
"So,do you guys have any questions?"

A guy got up n asked a question.I got mixed up,but its not that i didnot know the asnwer.

I gave him a wrong answer ,he ahd a grin on his face n said ,its wrong.

I retorted"Hey why did u ask me if you knew it much better then me"

Bacha smart ban raha tha:D