一般来说，满足( )，购买者可能具有较强的讨价还价能力。

A．供应方能够实行前向战略整合时

B．购买者能够实行后向战略整合时

C．供应方所提供的产品占购买者产品总成本的较大比例时

D．购买者的总数较多且单个购买者的购买量较小时

Woman: Bill, I want to have a few words with you about your performance in class lately.

Man: I know I’ve gone down. I just haven’t been studying as much as I ought to.

Question: What is Bill’s problem().

A. He doesn’t like to perform in class.

B. He doesn’t work hard enough.

C. He has gone away lately.

D. He feels depressed.