Given the task definition and input, reply with output. In this task, you will be shown a conversation and a question. You need to answer the question and choose the correct option based on the conversation. "W" and "M" in the conversations stand for "woman" and "man".

M: Do you like our new history teacher? W: I'm tired of his endless talking. He never gives us a little time to discuss things. M: You can't say that! He's a very knowledgeable person. W: But I can't see it., Question: What teacher are they talking about? (A) Their Chinese teacher. (B) Their history teacher. (C) Their politics teacher.
(B) Their history teacher.