单项选择题

Questions 1 to 3 are based on the following conversation. At the end of the conversation, you will be given 15 seconds to answer the questions.
Now, listen to the conversation.

In which case will the bank charge a fee

A.If the balance is below five hundred dollars.
B.If the interest rate varies.
C.If the customers open a new account.
D.If the customers want to check their account.