Explanation
Correct answer: D.
Choice D is the best answer. The convention being tested is pronoun-antecedent agreement. The singular pronoun “it” agrees in number with the singular antecedent “dark fiction” and clearly indicates that dark fiction uses horror tropes to challenge familiar ways of knowing.
Why the other choices are wrong
Choice A
Choice A is incorrect because the singular pronoun “one” is ambiguous in this context; the resulting sentence leaves unclear who or what uses horror tropes to challenge familiar ways of knowing.
Choice B
Choice B is incorrect because the first person plural pronoun “we” isn’t conventional as a substitute for “dark fiction.” It suggests that the readers, rather than dark fiction, use horror tropes to challenge familiar ways of knowing.
Choice C
Choice C is incorrect because the plural pronoun “they” doesn’t agree in number with the singular antecedent “dark fiction.”