The correct answer is: D. expertise, derivative
The word “expertise” means “special skill or knowledge in a particular area.” The word “derivative” means “coming from or based on something else.” In this case, the author is saying that the man was known for his great skill in a particular area, but his books were not original because they were based on the work of others.
The other options are not as good fits for the sentence. Option A, “advice, unconscious,” does not make sense because the author is not talking about the man’s advice. Option B, “skill, independent,” does not make sense because the author is not talking about the man’s independence. Option C, “knowledge, ignorant,” does not make sense because the author is not talking about the man’s ignorance. Option E, “dependence, indicative,” does not make sense because the author is not talking about the man’s dependence.