瓢虫鞘翅色斑由S、S、S三个复等位基因决定，这三个复等位基因可组成6种基因型，6种表型，其中纯合基因型为3种，杂合基因型为（）种。

By definition，a "spar deck" is the（）.

A.lower most continuous deck not broken by water tight bulkheads

B.after most weather deck above the main strength deck

C.upper or weather deck above the main strength deck

D.deck of light construction below the main or strength deck