It is difficult to come to a decision in regard to which aspects of modernism can be applied more to The Sun Also Rises than others; however, in this particular instance, I believe the two most applicable aspects to be the subversion of traditional values through departing from the standard methods of representing characters and violating traditional modes of narration through the use of the narrative device known as the stream of consciousness.
In Victorian literature, characters are often introduced and represented via the use of detailed and flowering prose; however, in The Sun Also Rises, the introduction of the main characters features as little information as possible—with the exception of Robert Cohn, whose background is discussed at length in the beginning of the novel. The Sun Also Rises is written as a first-person narrative as well, which is quite unlike more traditional Victorian literature.