The H ^- Atom Is Important in Protostars Because

The H ^- atom is important in protostars because it acts as a

A) source of friction, stopping the cloud from collapsing too rapidly.
B) source of infrared radiation, causing the cloud to cool off rapidly.
C) temperature regulator.
D) source of buoyancy, allowing the atmosphere of the protostar to expand.
E) source of easily detectable radio-wave emission.