【单选题】

{{I}}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.{{/I}} What is the disadvantage of the distance learning course

A、It is kind of expensive.
B．It lacks person-to-person contact.
C．It has a heavy schedule.
D．It is new, so it is risky.