(A) For head on elastic collision of sphere with wall, K.E. of sphere does not change but the sphere receives an impulse. Hence false.(B) If K.E. of a sphere changes its velocity and thus momentum must change. Hence false.(C) A force acting perpendicular to velocity changes momentum, but does no work. Hence true.(D) When a force does work, kinetic energy of body changes. If K.E. changes, velocity and thus momentum must change. Hence false.