A red giant loses a solar mass in 300,000 years via a superwind. After 0.6 million years, it has a mass of 12 M⊙. What was its original mass? (Give your answer in terms of M⊙)
a) 14 M⊙
b) 16 M⊙
c) 18 M⊙
d) 20 M⊙