The MOST Likely Mechanism for the Formation of a Star

The MOST likely mechanism for the formation of a star and planetary system is that the

A) star and planets slowly condensed to their present form from a gas and dust cloud.
B) star captured the planets as they drifted through space.
C) system was once a galaxy from which the star and planets are the remnants, after evolution.
D) planets were spun out of the star as smaller gas clouds and subsequently condensed.