Examine the model shown here for the planets' orbit around the sun. How should the student best label the arrows shown in the model?

A: The blue arrow shows inertia that keeps planets in motion while the yellow arrow shows the gravitational force by the Sun.


B: Both arrows show the electromagnetic attraction between the Earth and other objects in the solar system.


C: The blue arrow shows acceleration as the planetary motion speeds up throughout its orbit.


D: The yellow arrow shows momentum, as the mass of the Earth is affecting its speed.