While graceful is for a dancer, then eloquence will be for a speaker. Grace is exuded by a dancer when s/he dances. We always exclaim "How gracefully she dances!" etc etc. Likewise, for a speaker, eloquence is it's grace. Eloquence is the fluency or persuasive nature of a speaker, his ability to perfectly present his case.
Eloquent is the correct answer. Eloquent means fluid expression. A dancer that is graceful because their motion is fluid. A speaker is eloquent because their expression is fluid.
