Your master will like you if you are diligent.

Answer: Option D

Casual : relaxed and unconcerned. Obedient : complying or willing to comply with an order or request; submissive to another's authority.
Meticulous : showing great attention to detail; very careful and precise.
Hard-working : (of a person) tending to work with energy and commitment; diligent.
Diligent : having or showing care and conscientiousness in one's work or duties.

Synonym of Diligent is Hard-working