Answer:
B. elastic PE to kinetic energy
Step-by-step explanation:
As we know that when we stretch the slingshot to some distance then the elastic energy is stored into the sling which is given as

here we know that
k = elastic constant of the sling
x = stretch in the sling
now when we release the sling from that position then the shot will move with certain kinetic energy from it and sling comes to its natural length
so here we can say that elastic potential energy of the sling will convert into kinetic energy of the shot here so correct answer will be
B. elastic PE to kinetic energy