Antonym of LENIENT

Answer: Option D

Lenient : (of a punishment or person in authority) more merciful or tolerant than expected.
Obstinate : stubbornly refusing to change one's opinion or chosen course of action, despite attempts to persuade one to do so.
Annoyed : slightly angry; irritated.
Rude : offensively impolite or bad-mannered.
Harsh : unpleasantly rough or jarring to the senses.

Antonym of Lenient is Harsh