【单选题】

Man: That’s the most boring seminar I’ve been to in a long time.

Woman: Well, it wasn’t the regular speaker. She got sick at the last minute.
Man: I’m surprised they didn’t have a better substitute.
Question: What does the man mean
A．They should replace the regular speaker.
B．He hasn’t been to a seminar for a long time.
C．He didn’t expect the substitute was so poor.
D．The substitute was not as good as the regular speaker.