Correct Answer: Shrewd

Solution : The correct choice is the first option.

Astute: Astute describes someone who is perceptive, clever and has a keen ability to understand and judge situations accurately.

Shrewd: Shrewd is a synonym for astute. It refers to someone who is clever, sharp-witted and shows good judgement in practical matters.

The meanings of the other options are as follows:

• Dull: It means lacking interest or brightness.
• Impolite: It refers to behaviour lacking courtesy.
• Crude: It describes a lack of refinement or rawness.

Therefore, the right answer is shrewd.