Which of the Following Descriptions Characterizes the Newtonian Understanding of the Mechanics

Which of the following descriptions characterizes the Newtonian understanding of the mechanics of the solar system?

A) The natural motion of the planets is motion in a straight line. The planets are prevented from straight-line motion by the gravitational force of the Sun.
B) The natural motion of the planets is uniform circular motion. The gravitational force of the Sun distorts the orbits of the planets into ellipses.
C) The planets are held in their orbits by a gravitational balance between the Sun (which is closer) and the stars (which are farther away) .
D) The planets are held in their orbits by a balance between gravitation (attraction) and magnetism (repulsion) .