Please choose the correct ending to complete the given sentence: Tennis serve with ball bouncing: . a man in a red shirt at an outdoor tennis court

Ending1: of some sort throws a ball at a yellow ball, the yellow ball rolls into the net and the man and woman run to retrieve the ball. Ending2: says something to the camera and does some hand motions at the black object on the court. Ending3: is giving a tutorial on to return a serve and how to hold the racket. Ending4: does volley tennis and serves the ball.

Answer format: ending1/ending2/ending3/ending4