Which of the following is a difference between medium-mass stars and massive stars?

Which of the following is a difference between medium-mass stars and massive stars?
 
  A) Unlike medium-mass stars, massive stars can get hot enough to ignite carbon fusion.
  B) Unlike medium-mass stars, massive stars consume the hydrogen in their cores.
  C) Unlike medium-mass stars, massive stars ignite hydrogen shells.
  D) Unlike medium-mass stars, massive stars can become giants or supergiants.

Question 2

Which of the following is left behind when a star dies?
 
  A) A black hole
  B) A red giant
  C) A gray dwarf
  D) A yellow node

Question 3

In the context of supernova explosions, the _____ is a young remnant, only about 960 years old and about 9 ly in diameter.
 
  A) Lagoon Nebula
  B) Carina Nebula
  C) Eagle Nebula
  D) Crab Nebula

Question 4

Mathematically, the product of mass, velocity, and radius is called _____.
 
  A) specific gravity
  B) angular momentum
  C) linear energy
  D) spectral radius