下列选项中不属于结构化程序设计原则的是( )。

A．可封装

B．自顶向下

C．模块化

D．逐步求精

If two sailing vessels are running free with the wind on the same side, which one must keep clear of the other?（）.

A.The one with the wind closest abeam

B.The one to windward

C.The one to leeward

D.The one that sounds the first whistle signal