Some Protostars,when They Evolve onto the Main Sequence,are Fully Convective

Multiple Choice

Some protostars,when they evolve onto the main sequence,are fully convective and use convection to transport material all the way from the core to the surface.Which stars show this characteristic?

A) Only the smallest,with masses less than about 0.4 solar masses
B) Intermediate,with masses from about 0.4 solar masses up to about 4 solar masses
C) The largest,with masses above about 4 solar masses
D) All stars,regardless of solar mass