Answer:
D. Radioactive decay, nuclear fusion, nuclear fission
Step-by-step explanation:
Radioactive decay is a natural process. In this process the rate of production of radioactive elements is less than the fusion and fusion reactions. In fusion reactions, lighter elements are combined to form a heaver radioactive elements. In these reactions energy released is very high but nuclear waste is less than fission reaction. In fission reaction larger elements are broken down in small radioactive elements. Due to this reason, fission reactions have greater nuclear waste.