食入性中毒常用高锰酸钾洗胃，其浓度为（）。

A.1∶100

B.1∶5000

C.1∶10000

D.1∶15000

E.1∶500

—Please say something about Zheng He.

—Oh! He is the Ming dynasty explorer of ______ all the Chinese are proud.

A．who

B．whom

C．whose

D．that