Please choose the correct ending to complete the given sentence: Doing motocross: . two dirt bike riders dressed in full motocross gear

Ending1: sit on their motorcycles. Ending2: are intertubing along a mountain path. Ending3: arrive with an indian fan and load themselves onto the bikes. Ending4: are going through the forest and winding mountain turns back to the airport in montego city, spain.

Answer format: ending1/ending2/ending3/ending4