花生果是由下列哪一项发育而成的：（）

A、花冠和花托

B、子房壁

C、子房壁和胚珠

D、花托和胚珠

— Are you good at history, Rose?

— _____. But I will try to study it well this term. [ ]

A. That's all right

B. Not very good

C. No problem

D. Quite well