Please choose the correct ending to complete the given sentence: Assembling bicycle: A screen appears with instructions how to attach an instep bike trailer. a man

Ending1: is seen riding dirt bikes in a lane. Ending2: replaces the main tire using a spare tire along with another. Ending3: is showing how to attach an instep bike trailer on the back wheel of a bike. Ending4: does a routine on a tire.

Answer format: ending1/ending2/ending3/ending4