What prevents the man from taking the poets of 1960s course?

W: Hi, Mark, how is it going?
M: Well, not so great. I’ve got a big problem with the poetry course that’s required for my major.
W: Is that all filled up?
M: No, no, mere’s plenty of room, but there is a prerequisite. I’ve got to take an introduction to poetry before I can take the special course in poets of the 1960s and the introductory course is only offered in the evenings.
W: You don’t like evening classes?
M: No, that’s not the point. I work in the cafeteria every evening. I need the money to pay my tuition.
W: Can you ask someone to switch hours with you?
M: I wish I could. My boss just did me a favor by putting me on evenings. And he’ll hit the ceiling if I ask to change again.
W: Wait a minute. I have an idea. Have you checked the courses over at the community college? They might offer an introductory poetry course during the day.
M: Hey, that’s a great idea! I’m free this afternoon. I think I’ll go over and check it out.
W: Yeah, their courses are actually cheaper, and you can transfer the credits over there.
M: Thanks for the advice, Linda. I’ll let you know what happens.