Which of these correctly describes whether a girl holding a ball in the same position is doing work on the ball? a. the girl is doing work on the ball because the energy of the ball changed, even though it is not displaced. b.the girl is doing work on the ball because the energy in her muscles changed, even though the ball is not displaced. c.the girl is doing no work on the ball because she is not exerting any net force on the ball. d.the girl is doing no work on the ball because the ball is not displaced.