TOEFL Listening: ETS-TOEFL听力机经 - GQAOAMR1T1E3863HP$

What does the professor imply about master painters working in the late fifteenth century? A. They alone decided on the subject matter of their paintings. B. They had higher social status than painters from earlier in the century. C. They were not required to use as many expensive materials as in the past. D. It is impossible to know how much of an artwork they personally painted.