Do you agree or disagree with the following statement?

Imagine that you are in a classroom or a meeting. The teacher or the meeting leader says something incorrect. In your opinion, which of the following is the best thing to do?
1）Interrupt and correct the mistake right away
2）Wait until the class or meeting is over and the people are gone, and then talk to the teacher or meeting leader
3）Say nothing

Use specific reasons and examples to support your answer.