Final answer:
Rusty wants to dance, as indicated by his direct statement expressing his desire to engage in this activity.
Step-by-step explanation:
When Rusty says, "Now c'mon. Let's dance!" he is expressing his desire to dance. He is not interested in singing, eating, or leaving the place, as the other options suggest. Rather, Rusty is eager to engage in the physical activity of dancing, possibly to music or in a social setting.
The quote provided from Judy, where she expresses her disinterest in returning to what she refers to as an idi-otic dance, confirms that the activity in question is indeed dancing.