177。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. 与原句相同

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 originated 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

E. Originating, it is believed, from a small area on their foreheads, low-frequency sounds are emitted by elephants that may be used

我选的是B，答案选C，但believed的主语逻辑上不就是elephants了吗，而且that 指代的是foreheads，不是改变原意了吗？

这个是新东方250题里的，谁有这250题的全部讲解啊，能发给我吗？谢谢