Properties of
alpha particles
Beta particles
Gamma particles

Alpha is identical to a helium nucleus so it is two protons and two neutrons
It’s the least penetrating and can be absorbed by skin

Beta radiation had high energy electrons emitted from the nucleus and don’t come from a energy shell they come from when a nucleus splits into a proton
Can penetrate air and paper but stopped by a thin sheet of aluminium

Gamma has a short wavelength and high frequency and is electromagnetic so it can travel long distances
Most penetrating and can penetrate air paper and thin metal and can only be stopped by lead and lots of concrete

Ithink it is letter b, i may be wrong but i think that is the answer

What are you trying to ask?