单项选择题
In this section you will hear several conversations. Listen to the conversations carefully and then answer the questions that follow.
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.
A. 7 hours.
B. 8 hours.
C. 17 hours.
D. Several hours.