Explanation:

- Astute is an adjective used to describe someone who is clever and has the ability to accurately assess situations or people, often to their own advantage.

- Option 1: Shrewd – Similar to astute, shrewd refers to someone who is sharp-witted and demonstrates good judgment, particularly in practical matters.

- Option 2: Dull – Opposite of astute, dull refers to someone lacking sharpness or intelligence.

- Option 3: Impolite – Describes someone lacking manners; not related to intelligence or cleverness.

- Option 4: Crude – Refers to someone lacking refinement or sophistication; also not related to intelligence or cleverness.

Correct Answer: Option 1: Shrewd