Interstellar Exoplanets, Which Do NOT Orbit a Star, Are Most

Multiple Choice

Interstellar exoplanets, which do NOT orbit a star, are most likely

A) extremely rare, with only a few in the Galaxy.
B) much less common than those still bound to a star, with only about 1 such exoplanet per 1000 stars in the Galaxy.
C) less common than those still bound to a star, with only about 1 such exoplanet per 10 stars in the Galaxy.
D) more common than stars in our Galaxy.