Concept:When the adverb "enough" follows an adjective, that adjective must be in the positive degree, not comparative or superlative.
Explanation:The word "enough" is an adverb of degree that is placed immediately after the adjective it modifies.
For example: "He did not run fast enough to win the race."
In part (A) of the given sentence, "bravest" is the superlative degree of "brave".
Using a superlative form with "enough" is grammatically incorrect.
The adjective must be changed to its positive degree, which is "brave".
The corrected phrase becomes: "Are you brave enough to impeach or disclose..."
Parts (B), (C), and (D) are grammatically correct.
"To impeach or disclose" is a proper infinitive construction.
"The units or individuals" correctly serves as the object.
Hence, the error lies only in part (A).
Answer:Option A: (A)