Please choose the correct ending to complete the given sentence: BMX: People are riding bicycles on a track. a man

Ending1: is flipping and flying through the air. Ending2: in a red shirt is holding a long rod. Ending3: in a yellow shirt is demonstrating how to use a stop bike with pedals. Ending4: crashes and lands on the track.

Answer format: ending1/ending2/ending3/ending4