Answer:
D). Honest.
Step-by-step explanation:
Nick Carraway, the narrator of the novel, presents the story to the readers through his own point of view which if filtered by his personal thoughts or opinions.
He declares that 'he(Gatsby) is one of the few 'honest' people he has ever known' which is quite contentious because his behavior at fallacious and immoral conducts at various points in the novel stands contradictory to the narrator's view(which considers him as an honest man). Therefore, option D is the correct answer.