某同学在调查活动结束后，将有关的生物分成了农作物、家禽、家畜、宠物等。他所采用的分类依据是[ ]

A．形态结构

B．生活环境

C．生物用途

D．大小多少

— Do you want to be a policeman?

— ______. It's too dangerous. [ ]

A. Yes, it is

B. No, it isn't

C. Yes, I do

D. No, I don't