Answer: One listener interrupts the speaker by inserting an opinion.
Explanation:
In order for a successful group discussion to take place, it is important that all of the students listen to each other. Everyone's opinion must be taken into consideration, and everyone should be given a chance to express it. However, if the students interrupt each other while speaking, the speaker then cannot make his point clear and convey his idea. In this light, the action that would be the most disruptive to the discussion is - One listener interrupts the speaker by inserting an opinion. Of course, it is not appropriate to laugh at the opinion presented by another student either, but at least the student is not interrupted in the middle of his speech.
