Use a process of elimination.
If the ball is at rest and the drag is zero, (we agreed this when eliminating D) that rules out another of the answers doesn't it, leaving just 2.
Also, the force of the racket on the ball, F, only occurs on impact and gives the initial motion. After that, it's gone.
That rules out another of the options.
Now you tell me, what do you think it is? There's only one left.