【单选题】

Questions 4 to 7 are based on the following conversation.At the end of the conversation, you will be given 20 seconds to answer the questions. Now, listen to the conversation.

What might be a reason the man gets illA．He’s unwilling to be immunizeD、
B．He doesn’t get enough rest.
C．He forgets to take his medicine.
D．He doesn’t dress warmly enoug