This is an instance of dramatic irony, taking into account that this figure of spech is when the implications of a situation, speech, etc, are understood by the audience but not by the characters in the play.
Answer: A.
singular; idiosyncrasy
Explanation: It is not B. because it is not an innumerable talent and there is not a surplus of this talent. It is not C. because it is not insular or an idiom. It is not D. because people are not disconcerted or shocked to the point where they do not know how to act and this talent is not plural. This leaves you with A. singular;idiosyncrasy because it is a talent that not many people have and it is an unusual thing about him.
Hope this helps! :)
Probably B might be the answer
