He plays the part of a petulant young man in the film.

Correct option is D

The correct antonym of petulant is (d) cheerful.
· Petulant: Childishly sulky or bad-tempered.
· Petulant (Hindi meaning): चिड़चिड़ा स्वभाव.
· Example: His petulant remarks irritated everyone.
· Cheerful: Noticeably happy and optimistic.
Antonyms: Cheerful, good-humored, pleasant.
Synonyms: Sulky, irritable, peevish.
Meanings of other options:
· Industrious: Hardworking and diligent (परिश्रमी).
· Sulky: Bad-tempered and silent (उदासीन).
· Scrupulous: Very careful and diligent (ईमानदार).