Questions 7 to 10 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. Arthur is Paul’s ______.

A．Different styles of music depend on the particular material the guitar is made of.
B．Most styles of music have a specific guitar that embodies each genre’s sound.
C．A specific guitar when played with in a suitable manner can attain a perfect style.
D．A specific guitar can be used to play all kinds of mucsial styles in a perfect style.

A．expectation
B．unexpectedness
C．unchangeability
D．unpredictability