人都长有两只耳朵，下列有关的解释正确的是[ ]

A.人长两耳是为了左右对称的美

B.若没有两只耳朵人就不能听到声音

C.人长两只耳朵可以辨别声音传来的方位

D.人长两只耳朵可以增大听觉的频率范围

（）of the following need not be entered in the official logbook?

A.The testing of the internal combustion engine driven emergency generator at least once each month the vessel is navigated

B.The testing of storage betteries for emergency lighting and systems once each 6 months the vessels is navigated

C.The actual draft when the vessel arrives in salt water after department a port

D.The testing of the line-throwing appliance once every 3 months