Here's a problem to solve: A combination of processes occurs when stars are forming. Which is one process most likely associated with the formation of new stars?

Among the 4 following options, which is the correct answer?

- A: Hydrogen in the cores of the stars is exhausted.
 
- B: Material accumulates from stars that have died.
 
- C: Elements in the stars such as iron undergo fusion.
 
- D: Cores of stars become twice as massive as the Sun.
 