Answer: The correct answer is Option A.
Explanation:
For the given options:
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 mass of 4 units.
[tex]_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}\textrm{Y}+_2^4\alpha[/tex]
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. The beta particle does not have any mass.
[tex]_Z^A\textrm{X}\rightarrow _{Z+1}^A\textrm{Y}+_{-1}^0\beta[/tex]
Gamma decay is defined as the process in which an unstable nuclei gives off excess energy by a spontaneous electromagnetic process and thus releases [tex]\gamma -radiations[/tex]. These radiations does not have any mass.
[tex]_Z^A\textrm{X}^*\rightarrow _Z^A\textrm{X}+_0^0\gamma[/tex]
Nuclear reactions are defined as the reactions in which change of nucleus takes place.
Hence, the correct answer is Option A.
