_____ on the subject for half an hour, Liu Ying suddenly stopped. [ ]

A. To be worked

B. To work

C. Having worked

D. Having been worked

假定生产10公斤大米需要耗费6小时社会必要劳动时间，其价值的货币表现（价格）为30元，某农民生产10公斤大米只需耗费5小时劳动，这个农民把10公斤大米卖出后

A．会比别的农民多获得5元钱

B．会比别的农民少获得5元钱

C．会比别的农民多获得6元钱

D．会获得与别的农民同样多的钱