Answer: A) Hydrogen atoms fuse into larger helium atoms and release energy in the form of solar radiation.
Explanation:
Nuclear fusion is a process which involves the conversion of two small nuclei to form a heavy nuclei along with release of energy.
Nuclear fission is a process which involves the conversion of a heavier nuclei into two or more small and stable nuclei along with the release of energy.
The reactions which takes place in sun:
Overall reaction for the above series of reactions is given by:
Thus in the given reaction as the a heavier nuclei helium is being formed from combination of lighter hydrogen nuclei, this is a nuclear fusion reaction.