Oh dear.
Narrowed it to C and E:
C talks about the complications that can result when different cultures with different systems of discourse attempt to resolve disputes. Yeah, that happened, but I thought this was too specific and that E better encompassed what happened in the passage.
E talks about bringing to light problems faced by Native American tribes trying to establish claims within a legal system governed by the application of precedent (and problems with precedent then illuminates the problems faced by tribes attempting to resolve disputes with different systems of discourse).
It seems like the passage is talking about how following precedent is the problem, because precedent doesn't allow for different systems of discourse to count as evidence, which is why it is likely to assume (in question 4) that courts have become more likely to accept oral testimony in these kinds of claims.
I know I'm missing something. How do you pick C as the best choice?