Please choose the correct ending to complete the given sentence: BMX: A bicycle riding course with bumps is shown. a number of bicycle riders

Ending1: move along with one rest. Ending2: are then shown riding around on rafts, chasing dead ends. Ending3: are shown racing down it as well as shorter ones. Ending4: are shown going through the course.

Answer format: ending1/ending2/ending3/ending4