Correct Answer: 1970

Solution : The correct option is 1970 .

In field hockey, the "roll-in" and "push-in" restart techniques were replaced in 1970. The ball was rolled in along the sideline after being out of play before this modification. As part of the rule modifications to make the game faster and more exciting, the "push-in" was added. Players must push the ball back into play along the sideline to use the push-in, which makes the game restart faster and more smoothly.