What are the stages in the life of a low-mass star? Be able to describe each stage briefly.
a) Protostar, main sequence, red giant, planetary nebula, white dwarf
b) Protostar, red giant, main sequence, planetary nebula, white dwarf
c) Main sequence, red giant, protostar, planetary nebula, white dwarf
d) Protostar, main sequence, planetary nebula, red giant, white dwarf