【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 most probable relationship between the two speakers

A、
A、teacher and a student.
B．
A、brother and a sister.
C．
A、father and a daughter.
D．Two classmates.