<span> changing its shape
changing its mass
or changing its volume</span>
The momentum of the rolling ball will have less momentum than before the collision and the stationary ball will have more momentum after the collusion.
C is correct. Only a closed circuit can carry current, opening a switch disconnects the circuit and stops current from flowing. Remember, all current flows in loops, if you can't make a loop out of it, current can't flow, and opening a switch, assuming no other paths for current exist, will completely stop the current.
