54. Two planets of equal mass orbit a star. Planet A has a smaller orbital radius than planet B. Which of the following statements is correct? (A) Planet A and planet B have the same mechanical energy (potential energy plus kinetic energy). (B) Planet A has less kinetic energy, less potential energy, and less mechanical energy (potential energy plus kinetic energy) than planet B. (C) Planet A has more kinetic energy, less potential energy, and less mechanical energy (potential energy plus kinetic energy) than planet B. (D) Planet A has more kinetic energy, less potential energy, and more mechanical energy (potential energy plus kinetic energy) than planet B. (E) Planet A has more kinetic energy, more potential energy, and more mechanical energy (potential energy plus kinetic energy) than planet B.