Choose the option which best expresses the meaning of the idiom/phrase in bold in the sentence.
Despite all his efforts, Rajeev hit a brick wall in his investigation.

The idiom "hit a brick wall" means to face an obstacle that is impossible or very difficult to overcome.Option 1 (Encountered an insurmountable obstacle) correctly captures the meaning.Option 2 (Found unexpected support) is incorrect because it suggests assistance rather than difficulty.Option 3 (Made significant progress) is the opposite of the meaning.Option 4 (Discovered a secret path) is unrelated to the phrase.Thus, Option 1 is the best choice as it accurately conveys the meaning of the idiom.