This a passage-level purpose question. When answering these questions, think about what kind of audience the author intended to read this passage. Imagine that, after reading the passage, you had to describe to a friend what kind of passage it was (without mentioning the specific content). Common main purposes for RC passages are: 1. Presenting the different sides of a debate (without taking a stand) 2. Taking a stand on a debate 3. Criticizing one side of a debate/puzzling phenomenon (without taking a stand) 4. Presenting ONE side of a debate (without taking a stand or mention the other sides) 5. Giving historical or methodological background for the problem/phenomenon.
In this passage, the author presents a puzzling phenomenon (the introduction of rice to the Americas) and then she describes the process of ONE historian (Vernon) in theorizing and interpreting the historical evidence. The passage is focused on presenting Vernon’s theories about this phenomenon (answer choice C). The passage doesn’t attempt to describe her efforts to uncover evidence (answer choice A). It isn’t concerned with the historical background of the introduction of rice (answer choice B). It is not critical of Vernon or other historians (answer choice D), nor does it focus on the economic effects of this introduction (answer choice E). Thus, the correct answer is C.
I hope this clarifies things. Feel free to follow up if you still have questions.
