仓库内的气瓶放置应整齐，垛高不得超过多少层？

A.5层 

B.4层 

C.3层

Good seamanship while towing in heavy weather requires all of the following EXCEPT（）.

A.reducing speed to reduce surging on the towline

B.lashing down or stowing all loose gear

C.dogging all hatches and watertight doors

D.streaming all of your towing hawser