Please choose the correct ending to complete the given sentence: Welding: A man is wearing protective gear inside a workshop. He is welding a piece of metal with a machine. he

Ending1: continues working while sparks are flying. Ending2: uses a piece of metal to construct a door. Ending3: picks it up and tightens it against his thigh. Ending4: is using the machine's energy for building a fire.

Answer format: ending1/ending2/ending3/ending4