Three helium nuclei fuse together, forming one carbon nucleus. The mass of carbon is less than three times the mass of helium. When helium fuses into carbon, which of the following occurs?
a. Rest-mass energy is converted into some other form of energy
b. Some other form of energy is converted into rest-mass energy
c. The chemical reaction changed the total mass
d. The mass of three helium nuclei turned into one carbon nucleus and other smaller particles, such as protons and neutrons.