Option B: Nuclear fission reactions rarely occur naturally while nuclear fusion reactions occur in the stars.
Nuclear fission reaction is defined as formation of two or more atoms by splitting of large atoms. On the other hand, nuclear fusion reaction is formation of large atom from small atoms.
The splitting of large atoms into small atoms (nuclear fission) generally does not occur naturally because it requires high speed neutrons and critical mass of the substance undergoing fission.
Nuclear fusion reaction occurs in stars such as sun because it requires extremely high energy to bring two more proton closer to each other by overcoming electronic repulsion.
Therefore, nuclear fission reactions rarely occur naturally while nuclear fusion reactions occur in the stars.