Choose the correct adverb to fill in the blank:

She danced ________ at the party.

gracefully

The correct answer is option (1) gracefully.

An adverb is needed to describe how she danced at the party. "Gracefully" is the appropriate adverb here as it describes the manner in which she danced, indicating that she danced with elegance and poise. Options (2), (3), and (4) are not adverbs and do not appropriately describe the manner of the dance.