Thanks for the question! So we’re looking for an answer choice that the author says was a reason that could’ve discouraged historians from undertaking a comparative study of Russian serfdom and US slavery. For this answer, we should remember that this discussion occurred in the first paragraph, and so we can turn our attention there. Take a look at lines 13-16, where the author says that “some historians may have been put off by the forbidding political differences between nineteenth-century Russia and the United States,” since one was a monarchy and the other a democracy. Put off from what? Well, put off from the comparative study mentioned in the sentence before. So these lines are direct evidence for (A), that some historians were put off by major differences in the political systems of the two countries.
Now let’s take a look at (C), which says that some authors were put off by the failure of de Tocqueville to address the subject. It is true that de Tocqueville failed to address the subject, as we can see in lines 4-7. But the author is using that as an example of someone who compared the two nations a lot, just not in that respect. The author doesn’t say anywhere that other historians didn’t do a comparative study BECAUSE de Tocqueville didn’t do one. It’s more like “look, even de Tocqueville didn’t do it,” but that doesn’t mean that de Tocqueville not doing it was a reason that discouraged historians from doing the study.
Hope this helps! Feel free to ask any other questions that you might have.
