In this scenario, we have a moving soccer ball (with a force of 1.2 kN) striking a stationary soccer ball. When two objects collide and one is stationary, the dynamics of the collision will depend on the type of collision (elastic or inelastic) and the relative momentum of the two objects.
Assuming the collision is inelastic (which is common in soccer collisions), the stationary soccer ball will begin moving in the direction of the incoming ball, which is upfield. The ball that struck it will slow down due to the transfer of some of its momentum to the stationary ball.
Therefore, the correct result of the collision is: The stationary soccer ball will begin moving upfield and the ball that struck it will slow down.