Questions 18 to 20 are based on the following passage. At the end of the passage, you will be given 15 seconds to answer the questions. Now listen to the passage. Why does the professor mention the photograph of the painting Corn Belt city
A．It is the only record left of the painting. B．It is not an accurate representation of the painting. C．It has become more valuable .than the painting. D．It was destroyed with the painting in a fire.