Answer: D. fusion of hydrogen
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 follows a series of equations:
[tex]_1^1\textrm{H}+_1^1\textrm{H}\rightarrow 1^2\textrm{H}+_{+1}^0\textrm{e}+\text{energy}\\\\_1^2\textrm{H}+_1^1\textrm{H}\rightarrow 2^3\textrm{He}+\text{energy}\\\\_2^3\textrm{He}+_1^1\textrm{H}\rightarrow _2^4\textrm{He}+_{+1}^0\textrm{e}+\text{energy}[/tex]
Overall reaction for the above series of reactions is given by:
[tex]4_1^1\textrm{H}\rightarrow _2^4\textrm{He}+2_{+1}^0\textrm{e}+\text{energy}[/tex]
