请问大全174题

1.        Believed to originate from a small area on their foreheads, elephants emit low-frequency sounds that may be used as a secret language to communicate with other members of the herd.

(A) Believed to originate from a small area on their foreheads, elephants emit low-frequency sounds that may be used

(B) Elephants emit low-frequency sounds that are believed to originate from a small area on their foreheads, and they may use this

(C) Elephants emit low-frequency sounds, believed to originate from a small area on their foreheads, that they may use

(D) Originating, it is believed, from a small area on their foreheads; elephants emit low-frequency sounds they may use（C）

(E) Originating, it is believed, from a small area on their foreheads,

这题为什么不选B,我觉得答案C中的that还有指代不清的嫌疑啊!请高手指点!谢谢大家!

B中this的指代是错误的。

C中有问题的实际上是分词的修饰。believed可以修饰elephants或者sounds。不过，ETS似乎可以容忍这个修饰不清的错误。

请NN指正！