Question

1. the narrator in the book of sand describes the book he buys as infinite and __________

Answer 1

The narrator describes the book he buys and infinite and monstruos (option A). In fact, in his description he uses the word "monstruos" a couple of times.  The book might be seen as an object for nightmares, like something obscure and negative for its reader. He even said that it was "obscene" because it influenced really.