Question

Which example seems most like a formal discussion?

a debate between students about a topic from history
a chat among a group of friends about their favorite music
a phone call between students about their weekend plans
a conversation between a mother and son about his grades

Answer: A debate between students about a topic from history

Answer 1

It is the first one.

Answer 2

a debate between students about a topic from history

Step-by-step explanation:

Conversations of Mothers about grades are hardly formal talk, same goes to weekend plans. Chatting already implies that this is not a formal conversation.

This all is quite different than two students discussing about a period in history, a historical character, or something similar. In this case, the discussion is academic and most likely to be formal than the other situations.