Question

which type of star will become a black hole when it dies?
a protostar
a supergiant
a white dwarf
a red dwarf

Explanation:

Supergiant stars have extremely large masses. When they run out of nuclear - fuel and die, their cores can collapse under their own gravitational pull to form black holes. Protostars are in the early stage of star - formation, white dwarfs are the remnants of low - to medium - mass stars and lack the mass to form black holes, and red dwarfs are low - mass stars that will not form black holes either.

Answer:

B. a supergiant