The following diagrams are supposed to represent the solar system, with the Sun in the center and two planets orbiting it. The left diagram is a diagram without dark matter, while the right diagram shows the solar system embedded in a huge cloud of dark matter that is much much bigger than the solar system.

    A ) Star A should be moving faster than star C because the dark matter will slow star C down
    B) Star C should be moving faster than star A becuase the extra gravity from the dark matter will exert a greater force
    C) Both stars A and C should be moving at the same speed, because the dark matter has no effect
    D) You can't tell from the information given which star is moving faster

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