公安机关办理治安案件的期限，自受理之日起不得超过三十日；案情重大、复杂的，经上一级公安机关批准，可以延长（）。

A、三十日

B、六十日

C、九十日

D、一个月

—The Kiwi fruits in this supermarket are _______ sale now, and they are sold ______ the pound.

— Really? How much cheaper are they?

A．for; in

B．on; by

C．for, by

D．on, in