This question requires us to know that the correct idiom is "to research X" - as in "I went to graduate school to research genetics" or "I went to the library to research the subject of my paper". Adding any sort of preposition ("on", "about", "into") is not idiomatic when "research" is a verb. (Note: when "research" is a noun, we can follow it with a preposition - e.g. "I presented my research on the history of Sumer").

This allows us to eliminate all answer choices but E.

If we didn't know this idiom, B and C don't tell us that Baldwin lived in France when he wrote the books, just that he was in France. So we lose meaning with both answer choices and can eliminate them. Then, based on concision issues, we can likely pick E over A and D. However, knowing the correct idiom is the best way to get to the correct answer.