What Is the Difference Between a Bound Orbit and an Unbound

Multiple Choice

What is the difference between a bound orbit and an unbound orbit around the Sun?

A) An object on a bound orbit follows the same path around the Sun over and over, while an object on an unbound orbit approaches the Sun just once and then never returns.
B) A bound orbit is an orbit allowed by the universal law of gravitation, and an unbound orbit is not.
C) An object on a bound orbit has a gravitational attraction to the Sun, while an object on an unbound orbit does not.
D) A bound orbit is circular, while an unbound orbit is elliptical.