What Is the MOST Important Process That Causes a Protostar

What is the MOST important process that causes a protostar to stop accreting mass?

A) Radiation and particles from the hot protostar push infalling matter away from the protostar.
B) Other protostars formed in the vicinity pass randomly through the infalling material and eventually disperse it.
C) The dense core spins up as it collapses, and eventually the infalling matter is held away from the protostar by the centrifugal force.
D) All of the infalling matter has been used up in the accretion.