Choose the alternative which can replace the bold word without changing the meaning of the sentence. Despite his perspicacious observations, his advice was often ignored.

In the sentence, "Despite his perspicacious observations, his advice was often ignored," the word "perspicacious" means highly perceptive, sharp, or having keen insight. Here are the options provided: 1. Astute – This means shrewd, perceptive, and having keen insight, making it the closest synonym for "perspicacious." (Correct) 2. Vacuous – This means lacking intelligence or thought, which is the opposite of perspicacious. (Incorrect) 3. Dubious – This means doubtful or uncertain, which does not match the meaning of perspicacious. (Incorrect) 4. Trivial – This means insignificant or unimportant, which does not relate to being insightful. (Incorrect) The word that best replaces "perspicacious" without changing the meaning of the sentence is: (1) Astute.