TOEFL Listening: TPO-TOEFL听力TPO - R7V180V1W012W2Y1R$

Why does the professor say this: A. To indicate that she is unsure about the origin of the materials. B. To suggest the Natufians settled a large area. C. To point out how technologically advanced the Natufians were. D. To help students understand why the evidence of sedentism has been questioned.