The picture below shows a NASA image of the Oort cloud, a sphere of objects that are thought to surround Earth's solar system at a distance of up to one light-year from the Sun. If the Oort cloud does exist, which of the following could explain why the objects in it may have formed this spherical shape?
A
They are held in orbits by the Sun's gravitational force.

B
They are held in Earth's solar system by Neptune's magnetic field.

C
They float freely in space because the Sun's gravitational force is too weak to hold them in orbit.

D
They are held in stationary positions around Earth's solar system by other stars in space.