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:
![4_1^1\textrm{H}\rightarrow _2^4\textrm{He}+2_(+1)^0\textrm{e}+\text{energy}](https://img.qammunity.org/2019/formulas/chemistry/college/bbleoovbd9crqovvtvpz9lt8wmfkrk6lp8.png)
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.