TOEFL Listening: TPO-TOEFL听力TPO - 3MR2Y6U13U8M45ALR$

What can be inferred about the professor when she says this: A. She realizes that she just contradicted a statement she made earlier B. She is about to discuss another aspect of the topic C. She thinks the answer to her question is obvious D. She wants students to recall a case that she has already discussed.