He does every job with great zeal and vigour.

A. indifference

B. constraint

C. passion

D. difficulty

Answer: Option A

Solution(By Examveda Team)

Zeal : great energy or enthusiasm in pursuit of a cause or an objective.
Indifference : lack of interest, concern, or sympathy.
Constraint : a limitation or restriction.
Passion : strong and barely controllable emotion.
Difficulty : the state or condition of being difficult.

Antonym of Zeal is Indifference