Why is E correct? Why is B incorrect?

@Ryan-Mahabir, Lines 28-31 tell us that she conducted a research project into traditional Caribbean dance forms, with special interest in their origin in African culture. We can thus infer that these dance forms were influenced by the traditions of non-Caribbean (African cultures) as (E) states. (B) is incorrect because it is unsupported by the information in the passage. The author tells us that "various forms of [dance-isolation] technique have long been essential to certain African, Caribbean, and Pacific Island cultures (lines 9-11), this information suggests that the dance forms she studied in 1935 did not represented the first use of dance isolation outside of Africa, but the technique has been essential to other cultures for a long time.

I narrowed it down to C and E. I can see why E is correct, but why is C incorrect?

^^ I have the same question!

C is wrong because the passage never tells us that the dances she observed in the rest of the world shared rhythmic characteristics with those in North American ballet. It tells us that she adapted some elements of such dances into later ballets, but we have no idea which elements she borrowed, and hoe much she modified those elements in her borrowing. We don't really know how similar the source material was to the eventual ballet.