Rajesh is a shrewd person.

Answer: Option C

Shrewd : having or showing sharp powers of judgement; astute.
Boisterous : noisy, energetic, and cheerful.
Aggressive : ready or likely to attack or confront; characterized by or resulting from aggression.
Foolish : lacking good sense or judgement; unwise.
Intelligent : having or showing intelligence, especially of a high level.

Antonym of Shrewd is Foolish