TOEFL Listening: ETS-TOEFL听力机经 - C713PPB5IU2O783ZP$

Why does the professor say this: A. To imply that researchers used autoradiography somewhat recklessly in the investigation B. To stress the importance of preparation in the science of art examination C. To emphasize the extraordinary nature of the research into Rembrandt's works D. To point out the limitations researchers faced when they analyzed Rembrandt's art