I'm not sure that there's a single correct answer in that multiple choice question about Ernest Hemingway's writing style, but I think that I can safely rule out two answers.
"A. Remove all uncertainty.." is not a plausible answer. No self-respected modernist would try to use language without uncertainty, and Hemingway definitely presents uncertainty in a number of his works. For example, it's never completely clear what the topic of discussion is in the short story "Hills Like White Elephants: or what the nature of Jake Barnes' wound is in The Sun Also Rises. The reader gets a pretty good idea, sure, but the characters and narrator tend to talk around subjects rather than about them, a tendency that creates rather than removes uncertainty.
"C. Deemphasize the importance of language..." is equally impossible as an answer. Like all serious writers, Hemingway was closely attuned to language and often worked very long and hard to get the right word for what he meant. The drafts of his manuscripts are full of extensive revisions and rewritings of his material.
Of the remaining two answers, B and D, I think that I prefer the answer B. Or D! I really can't decide which seems most true. I also don't even think it's true that Hemingway always uses a "direct, unadorned style of writing." This characterization does not fit his very long and rich descriptions of the Spanish landscape in The Sun Also Rises, for example.