183. The KwakiutI recognized one social unit larger than the tribe—the confederacy, which was a cluster of loosely knit, informally related neighboring tribes who interacted with themselves more often than between other tribes.

A. tribes who interacted with themselves more often than between

B. tribes who interacted among each other more often than among

C. tribes who interacted with one another more often than with

D. tribes, interacting among each other more often than between

E. tribes, interacting among one another more often than with

求教大家。。。完全没头绪

平行： ==》 排除 A D E

比较 B C 

B among each other ... than among other ... ==> each other 和 other 不能搭配

C with one another  ... than with other....==> one another ... other

==> 选C

个人意见，open to discuss

个人观点：

A interact with...more often than between 不平行
B among 三者以上，后跟each other 不对
C 对， interacted with....than (interacted)with...平行，第二个with前的动词跟前面谓语一致，省略
D  among 错，且among...than...between...不平行
E  among...than...with不平行

 D E 的ing形式可能修饰前面整个句子,排除

A with和between 不一致,不好

B among 三者以上，后跟each other 不对

C with, with 好