The answer is not A, since a rhetorical question would not be answered and Tiana seems to want an answer. I think the answer is B, since procedural questions are typically those which ask why or how. The answer likely is not C, since a forced-choice question would have limited answers and it doesn't seem that Frank's options are very limited. I feel like the answer might be D, as discussing direct evidence from the book could move the discussion along. Out of B or D, I think Tiana is probably using B.