Answer:
The correct answer is C: Disposal of radioactive waste.
Step-by-step explanation:
During nuclear fission reactions, many intermediate radioisotopes are produced. For example, uranium releases different mass distribution isotopes and these isotopes emit radiations.
Most harmful isotopes for the environment are strontium and cesium because these have half-lives and an inclination of mixing in food chains.
When radioactive wastes are removed from nuclear reactors they flow towards the swimming pool and also have the tendency to isolate the short-lived isotopes from the environment.
Therefore, radioactive waste disposal has always remained a major problem