Answer:
a.) kinetic energy from the mallet is transferred first to the orange ball and then to the purple ball.
Step-by-step explanation:
It is not mechanical like in B, potential energy is not passed from ball to ball like in C, and it is not electromagnetic like in D. Therefore, it is A because the mallet hits(kinetic) the orange ball then the orange ball rolls(kinetic) into the purple ball so that the purple ball rolls(kinetic)