Questions that ask about the primary purpose of a paragraph normally have a correct answer that paraphrases the first sentence.
Why?
The test is asking us, "How did this specific paragraph function in relation to the big picture?" And good writers make that clear in the topic sentence to each paragraph. They explain the connective tissue between the previous paragraph and the current one.
In this passage, the third paragraph begins with "As a case in point ..."
So we know that the 3rd paragraph is designed to provide a supporting example for the final claim of the 2nd paragraph.
The 2nd paragraph was basically saying appreciation of Asian settlers' actions is an important part of telling the full story of the history of 19th century Pacific Coast settlement. The 3rd paragraph aims to flesh out that claim.
A) if the Chinese settlers just followed typical patterns, it would not be so "integral to the history of the region". (line 35)
B) we know there is little written evidence of Chinese settlers from 21-22. The 3rd paragraph is set up by saying, "We need to consider their actions". And the 3rd paragraph itself is a list of their actions. It has nothing to do with written evidence.
C) this is definitely accurate; this paragraph contains examples of how Asian settlers viewed/used the land differently.
D) this paragraph is not about any fight between historiographers. Some historiographers are bucking tradition by studying the actions described in the 3rd paragraph, but the 3rd paragraph itself does not discuss historiographers at all.
E) "inconsistent" on LSAT = "contradictory". This is similar to choice (E) in Q8; the passage isn't saying that the traditional history of the region is contradicted by the recent attention to Asian settlers. It's saying that the traditional history was incomplete. Studying the actions of Asian settler supplements / augments what we already knew about the region from traditional sources.
(C) is our answer.