Answer: Option (a) is the correct answer.
Explanation:
Nuclear fission is defined as a reaction in which a heavy nucleus splits into two or more small nuclei along with emission of energy.
For example, [tex]^{235}_{92}U + ^{1}_{0}n \rightarrow ^{139}_{56}Ba + ^{95}_{36}Kr + 3^{1}_{0}n[/tex]
So, the given diagram shows a large nucleus is splitting into two small nuclei. Therefore, it is a nuclear fission reaction.
Whereas a nuclear reaction in which two small nuclei combine together to result into the formation of a large nucleus is known as a nuclear fusion reaction.
Thus, we can conclude that the reaction depicted in the figure would take place in fission reactor.
