The answer is: a. dna changes.
Depands on radiation energy, radiotion can cause smaller or bigger DNA changes, mutations and death.
In order from highest to lowest frequency of the EM spectrum: gamma rays, X-rays, ultraviolet radiation, visible light, infrared radiation and radio waves.
Gamma rays are the electromagnetic waves with the shortest wavelengths (1 pm), highest frequencies (300 EHz) and highest energy (1,24 MeV).
Gamma rays contain much more energy (most penetrating) than radio waves because they have a greater frequencies.