Please choose the correct ending to complete the given sentence: Welding: Various people are shown in a workshop working while pushing objects, driving machinery, working machinery and etcetera. a woman

Ending1: is seen speaking backwards and another speaking the opposite direction. Ending2: is shown putting a long metal piece into a large machinery and the words " today's topic: welding " appears on the screen followed by a person wearing a mask and welding with a torch. Ending3: talks to the camera while people go on and off the equipment. Ending4: then shows off a machine that can be used in wave exercise.

Answer format: ending1/ending2/ending3/ending4