The Kwakiutl 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.
Clue: comparison word - interacted with .
(A) tribes who interacted with themselves more often than between
Interacted with ….more often than between .(with) preposition is missing. Also, it has meaning error. Interacted with themselves.Only crazy people do that more often. Eliminate
(B) tribes who interacted among each other more often than among
Interacted among - error. Each other should be used to represent two people. Here, we are talking about tribes.Eliminate
(C) tribes who interacted with one another more often than with
Keep it
(D) tribes, interacting among each other more often than between
Among should be used for representing more than 2 people. Each other should be used for representing interaction between two people. Eliminate
(E) tribes, interacting among one another more often than with
Comparison error. Among …..with ( unnecessary)
So, C should be the best option available
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