大大的怪题

shawnshao

Tektites, which may have been propelled to Earth from lunar volcanoes, are much like the volcanic glass obsidian, but their chemical composition is different than any terrestrial lava; they contain far less water than obsidian does and none of its characteristic microcrystals.

(A) is different than any terrestrial lava; they contain
(B) is different than any terrestrial lava’s, containing
(C) is different from that of any terrestrial lava; they contain
(D) differs from any terrestrial lava in containing
(E) differs from that of any terrestrial lava’s, containing


比较旧的题目  这个帖子里也出现过  但没有特别细的讨论
http://forum.chasedream.com/thread-36523-1-1.html

我做的时候觉得 没有一个是对的   正确答案是C

但谁能给我解释一下 "they contain"  和 “ its characteristic microcrystals.”  代词的数量是怎么解释呢  句子怎么理解呢  谢谢