Please choose the correct ending to complete the given sentence: Assembling bicycle: He starts off by turning the axle of the wheel with a pair of tongs to position the axle in the center. then he

Ending1: starts bending the wheel to adjust it with the mallet. Ending2: pumps some liquid into the tip of the wheel with the tongs to excite the wheel. Ending3: takes a brush and starts to work on the driver side tire. Ending4: fixes the center nut and uses a wrench to loosen it.

Answer format: ending1/ending2/ending3/ending4