TOEFL Listening: ETS-TOEFL听力机经 - 83I5I_E9X7MK5Q33P$

Why does the professor say this: A. He believes that this instrument took a very long time to complete. B. He does not understand how an ancient person was able to create the instrument. C. He is very impressed with the meticulous process of making the instrument. D. He wants students to try to think about how this musical instrument was created.