Final answer:
If a planet were stopped momentarily in space and then released, it would continue orbiting the sun. This is because the gravitational forces and the planet's inertia would make it resume its original path around the sun.
Step-by-step explanation:
If you could stop a planet for just an instant and then let it go, the correct answer would be c) It would continue orbiting the sun. According to Newton's laws of motion and universal gravitation, once an object in motion is not subjected to any other forces, it will continue on its original path due to inertia. Thus, halting a planet briefly without changing any other physical properties or forces acting upon it means the planet would resume its motion in orbit around the sun. The gravitational pull between the planet and the sun would continue to keep it in orbit.
Migratory interactions between newly formed planets and the surrounding circumstellar disk are complicated, but it does show that planets can lose energy and spiral inward unless they reach a point where they can stabilize and continue to orbit. Planet motion is governed by the balance between inertia and gravity; without an additional force, a planet does not simply fall into the sun or get expelled into space if momentarily stopped.