Correct answer: A. Alpha particles are 20 times safer than other types of radiation.
Alpha, beta, gamma, and X-rays are the forms of ionizing radiations. Alpha radiations are emitted when an atom emits alpha particles with 2 neutrons and 2 protons. These particles ionize matter due to their charge and mass. Alpha particles cannot penetrate the outer layers of the skin, but when present inside the cell they can be very damaging as they lose their energy within short distances ionizing the matter present around. Therefore, alpha particles cause more damage than other forms of radiations.