The correct option is A gene mutations
The hazards posed by radiation depend on its interaction with living tissues. At the molecular level, the electrons set in motion by ionising radiation can directly affect cellular macromolecules such as DNA. Radiation can also act indirectly by ionising water molecules to create reactive molecules or free radicals that can in turn, attack DNA or other cellular components as oxidising agents. Both direct and indirect mechanisms cause damage to the cell, particularly as a result of damage to DNA or gene mutation.