In the diagram, planets A, B, and C have the same mass. Which of these statements is true about the motion of these planets? A. Planet A will take the longest time to complete an orbit, while planet C will take the shortest time. B. Planet A will take the shortest time to complete an orbit, while planet C will take the longest time. C. The combined gravity of planets A and C will cause planet B to take the longest time to orbit. D. All the planets will take the same amount of time to complete one orbit.