A radioactive source emits three types of radiations. The radiations are :

The correct options are
A $\alpha$
B $\beta$
C $\gamma$
When the nucleus of a radio nuclide spontaneously gives up its extra energy, that energy is called ionizing radiation. Ionizing radiation may take the form of alpha particles, beta particles, or gamma rays. The process of emitting the radiation is called radioactive decay.