My question is briefly, how to handle silly questions? by silly, I mean questions that are unrelated to the material of the course.

First, I am TA. A student, recently, asked me at the end of a lab session, a very silly question. I say silly because: _1) it is not related to the lecture, 2) it is asked at the end of a lecture - and the class room was already full with the students of the next class, and 3) I have previously talked about this issue. __

The student insisted that I answer his question many times. So, I told him: "It is already late, but let me know about your question" .. when he asked it, I told him: "you can't be serious, this is not a question!"

He got upset, and he told me: "You are paid to answer my questions!" ..

I got angry, but. . how should I handle similar situations?