Heavier elements require higher temperatures to fuse. After stars run out of hydrogen in their cores, they leave the main sequence, collapse, and eventually get hot enough to fuse the helium in their cores into carbon. As discussed in the previous chapter, the Sun will never get hot enough to fuse carbon. Which of these hypothetical situations would allow the temperature of the Sun's core to rise enough for carbon fusion to be possible?A. Add mass to the Sun.
B. Increase the radius of the Sun.
C. Convert all of the Sun's hydrogen into carbon.
D. Decrease the radius of the Sun.

As heavier the elements need a high temperature to fuse at a higher the stats may run out of the hydrogen and they collapse leaving the main set of sequence stars and collapses and get hot enough to fuse the helium gas in their cores as carbon.

In such a hypothetical situation the temperature of the sun core would rose up and also allow for the temperature of the score to rise enough with the carbon so as the fusion to take place. Thus the addition of the mass to the sun would be possible.