6678. I don’t see why he should be so obsequious to his brother just because the latter is rich.

✅ The correct answer is option C.
Kind : a group of people or things having similar characteristics.

Unfriendly : not friendly.

Servile : having or showing an excessive willingness to serve or please others.

Offensive : causing someone to feel resentful, upset, or annoyed.

Obsequious : obedient or attentive to an excessive or servile degree.

Synonym of Obsequious is Servile