Which of these sentences contains an adverb in the comparative form?
A. Vincent Van Gogh’s paintings are in museums all over the world, for he is a great artist.
B. The Grant Street Library has the most books of all the libraries in the city, so it is often busy.
C. Fernando drives more carefully than Stephan does, so most people prefer riding with Fernando.
D. We travel farthest to reach Oakland Mall, but the trip is worthwhile because of its variety of stores.