Write the next sentence in the following story.

A group of four boys are at a table. as a timer

Pick from: [i] counts down, they add ice cubes to the machine to make a drink.; [ii] counts down, the three boys wearing white shake hands.; [iii] begins, they begin to play a game of beer pong.; [iv] counts, a boy is trying to solve a rubik's cube.;. The answer should be
[iv]