How to deal with rude interruptions in a seminar?
The following situation has occurred several times with B (the same person, in the audience), A (a speaker, different from time to time), and C (the audience, mostly the same).* A is presenting some topic at a seminar* A presents some background material X* B interrupts, says something like "how many in C already know about X?" (suggesting that A should skip it).* C, who is generally quite annoyed with B, answer in some half-hearted way, usually letting A go on with the background materialI find the behavior of B rude (I can explain in more detail if this is disputed). If it is rude, then what is a good way to call it out? I will soon be A, and would like to deal with this in a light-hearted way but still sending a clear message.EDIT: Thanks for the many comments, and sorry if I did not make the question clear enough from the outset. It turns out there are actually three questions:1. Is B's behavior rude and underhanded?2. If someone is rude and underhanded in this way during a presentation, should one call it out?3. How to call out improper behavior / make it stop (in this particular case)? Given that the obvious methods (raised eyebrows, few answers from C, et.c.) have all failed.baldPrussian gives good suggestions in his answer, but I don't think they work in my particular situation. The polling is seldom actually carried out, and I think little is lost in thinking of the polling requests as slinging insults or statements-of-superiority-of-B at the A. Of course the simplest thing is just to ignore B, but that feels wrong (in the same way lying feels wrong).