Explanation
Correct answer: C.
Choice C is the best answer because it most accurately states the main purpose of the text, which is to describe a collection of medieval maps and how it was created. The text begins by mentioning Muhammad al-Idrisi’s collection of maps of lands known to medieval Arabic and European scholars. It then states that the Norman king Roger II hired al-Idrisi to create the collection and details al-Idrisi’s methods of creation: consulting Arabic and Greek maps and interviewing travelers. In short, the text presents a collection of medieval maps and then goes on to describe how that collection came to be.
Why the other choices are wrong
Choice A
Choice A is incorrect because the text describes a collection of maps and the process of creating that collection but does not discuss the benefits of studying mapmaking in general.
Choice B
Choice B is incorrect because though the text mentions that al-Idrisi interviewed travelers, the text does not describe how those travelers created maps.
Choice D
Choice D is incorrect because though the text mentions that al-Idrisi consulted Arabic and Greek maps, the text does not offer a comparison of Arabic and Greek mapmaking techniques.