Read the following excerpt from theodore dreiser's "my brother paul." based on the context, what does the word ebullient mean?

his temperament, always ebullient and radiant, presented him as a clever, eager, cheerful, emotional and always highly illusioned person with so collie-like a warmth that one found him compelling interest and even admiration. easily cast down at times by the most trivial matters, at others, and for the most part, he was so spirited and bubbly and emotional and sentimental that your fiercest or most gloomy intellectual rages or moods could scarcely withstand his smile.

temperamental
overwhelmed
exuberant
frenzied
sympathetic