Answer: Carbon inside a star is most likely formed by nuclear fusion process.
Explanation:
For the given options:
Nuclear fusion reaction is defined as the reaction in which lighter nuclei combine together to form a single heavier nuclei.
Nuclear fission reaction is defined as the reaction in which the heavier atoms splits into two or more lighter atoms. The number of atoms formed in this reaction increases from the given atoms.
Beta decay is defined as the process in which beta particle is emitted. In this process, a neutron gets converted to a proton and an electron.
Alpha decay is defined as the process in which alpha particle is emitted. In this process, a heavier nuclei decays into a lighter nuclei. The alpha particle released carries a charge of +2 units.
In a star, carbon atom is formed by the process known as triple alpha process.
This process is a set of nuclear reaction in which 3 alpha or helium nuclei combine together to form carbon nucleus.
The equation representing the fusion process follows:
[tex]_2^4\textrm{He}+_2^4\textrm{He}\rightarrow _4^8\textrm{Be}+\gamma\\\\_4^8\textrm{Be}+_2^4\textrm{He}\rightarrow _6^{12}\textrm{C}+\gamma[/tex]
Hence, carbon inside a star is most likely formed by nuclear fusion process.
