请教大全896题

请教大全中的一道题目。该题中their 后面为何不用复数，谢谢

896.        Unlike other arachnids, which have their nerve cells evenly distributed along their bodies, the scorpion’s nerve cells are clustered in its head, like a mammal’s.

(A) bodies, the scorpion’s nerve cells are clustered in its head, like a mammal’s

(B) bodies, the scorpion’s head had a cluster of nerve cells, as a mammal does

(C) body, the scorpion has a cluster of nerve cells in its head, as a mammal does

(D) body, nerve cells are clustered in the scorpion’s head, like a mammal’s（C）

(E) body, a cluster of nerve cells is in the scorpion’s head, like a mammal’s

unlike表示比较，出现这个标志后，unlike之后跟什么词，主语也要用对应的词（人人对应，物物对应，词性，含义都要对应）。

文中未划线的other arachnids是物（应该是动物，抱歉懒得查了，反正肯定不是head和cell），那么之后的主语必然是the scorpion 。选C