What happens next in this paragraph?

Suddenly there are lit up people wearing light suits that are dancing on the black area and they change from 1-7 people, and alternate suit colors from white, then to red and then back to white again. their light suits
Pick from: [I] appear on the ground and one of the man takes one of the suits off and bursts out laughing white light and begins to dance in the suit. [II] go out and the dance is over. [III] are reflected by the main cube in the lobby of the building. [IV] slows down a bit as they stay in the structured mode and they continue to move the red lights to dance.
[II]