Final answer:
The antonym for the word 'sober' in the passage is 'fun,' as it contrasts with the serious nature implied by 'sober.'
Step-by-step explanation:
The word sober in the passage is used to describe a demeanor that is serious or subdued. Therefore, the antonym, or the word with the opposite meaning of sober, would be fun, as it suggests a light-hearted and amusing nature. The words black and shone relate to visual descriptions, and asked is a verb indicating the action of posing a question, none of which serve as antonyms to sober.