Please choose the correct ending to complete the given sentence: Doing motocross: The camera man pans across the motocross course with different riders riding on different parts of the course. A group of motocross riders perform some jumps at high speed from multiple directions. a group of motocross riders

Ending1: surmount the long run in the course during an aerial performance. Ending2: ride on the motocross course performing tricks and other riding skills. Ending3: briefly walk across the course wearing stilts. Ending4: performs jumps from multiple directions side to side on the side of a stationary bicycle.

Answer format: ending1/ending2/ending3/ending4