The answer is D: Good writing.
Jorge Luis Borges, the great Argentinian author, repeatedly said that, if anything, he considered himself to be a reader before anything else. Undoubtedly, to become a better writer one has to practice writing, but, according to some of the greatest literature masters —like Roberto Bolaño would also say—, one needs to engage the history of literature, first and foremost, as a reader, so that one can get immersed in its intricacies and be able to, with a critical eye, detect good writing from bad writing —it does not matter if it´s a novel or nonfiction, the point is to be exposed to good writing.
