Any suggestions for interactive presentation software ?

My uni club is organizing a conference next week and we are still looking for a decent interactive presentation software for our panel discussion.
I look for:
– Multiple choice and text question
– Q&A feature with queries updated live
– Powerpoint integration so that we don’t have to redesign our slides from scratch
– Can host appr 300 people at a time
Pls reply down below with ur suggestions, many thanks