Answer the following question given this paragraph: 

Eventually a main sequence star will use up all of its hydrogen. It then starts to fuse helium atoms into larger elements like carbon. At this time, the star’s core will collapse inward. The star's outer layers will spread out and cool. The result is a larger star that is cooler on the surface, and red in color. The star is now a red giant .


Q: When a star's core collapses inward while the outer layers spread and cool, what "colorful" celestial body forms?

 Choices:

- blue giant

- green giant

- white giant

- red giant

A:
red giant
