The argument concludes that North Americans who travel to Europe for the first time should include significant time in Italy on their itinerary.
Why? Because in order to develop an in depth appreciation of a continent, one must acquire a thorough knowledge of at least one country and Italy is one of the easier countries for North Americans to get to know.
So, it is integral to the reasoning that Italy should be included in the itinerary because North Americans seem to find it EASIER to get to know. This is the key difference between (A) and (C).
Answer choice (A) is advocating a type of music that is "more difficult to play," whereas answer choice (C) is advocating putting Edith Wharton in U.S. Literature curricula since she is "the most accessible," i.e. easier to understand than other classical U.S. writers.
Thus, answer choice (C) more closely conforms to the principle stated in the argument.
Hope that clears things up! Please let us know if you have any other questions.
