Newton's Cradle

Choose the best explanation of how a ball striking the four stationary balls causes the one on the other end to move.

a
All the balls start with kinetic energy. An outside force moves one outer ball and then the kinetic energy is converted to potential energy. Potential energy travels through the balls and moves the last ball to swing out.
b
All the balls start with potential energy. An outside force moves one outer ball and then the potential energy is converted to kinetic energy. Kinetic energy travels through the balls and moves the last ball to swing out.
c
All the balls start with a total energy. An outside force moves one outer ball and then the total energy is converted to high potential energy. Potential energy then converts to kinetic energy, which travels through the balls and moves the last ball to swing out.