33. A block on a horizontal frictionless plane is attached to a spring, as shown. The block oscillates along the x -axis with amplitude A. Which of the following statements about energy is correct?
(A) The potential energy of the spring is at a minimum at x=0.
(B) The potential energy of the spring is at a minimum at x=A.
(C) The kinetic energy of the block is at a minimum at x=0.
(D) The kinetic energy of the block is at a maximum at x=A.