The correct option is C tame
The word 'wild' refers to lacking discipline or restraint.
Option A, tame refers to being disciplined and domestic.
Option B, meek refers to being submissive.
Option C, mild refers to something not severe, serious or harsh.
Option D, domestic relating to the running of home or to family relations.
Thus, according to the meaning, the word 'tame' is the opposite of the word 'wild'.