To identify the antonym for "sullen", one must grasp its definition and then choose the word with the inverse meaning from the provided selections.
Definition of "sullen": Sullen describes a person exhibiting gloominess, moroseness, or silent resentment, typically in a poor mood.
Analysis of Options:
The accurate antonym for "sullen" is genial, as it conveys a friendly and cheerful demeanor, directly opposing a gloomy and resentful disposition.