单项选择题

W: There are so many children at the school. I wonder how the teacher keeps track of them.
M: I used to get cold feet at the thought of teaching a class of 100. That’s a fact.

What do we know from the conversation()

A. The man used to be a teacher.
B. The woman is teaching a class of 100 children.
C. The woman thinks it easy to teach.
D. The man thinks it quite difficult to teach.