Please choose the correct ending to complete the given sentence: Walking the dog: . a dog who is missing his front legs

Ending1: is being held by a person from behind as he tries to legs free. Ending2: is sweeping the floor in a room in the back of a store. Ending3: is walking across a lawn. Ending4: has his front paw over his mouth and he manages to get off the floor.

Answer format: ending1/ending2/ending3/ending4