Answer:
The correct answer is beta particles.
Step-by-step explanation:
A positron or an electron, which is discharged at a very greater speed and energy from a nuclear decay reaction is known as a beta particle. In comparison to beta particles, the alpha particles are much heavier as it comprises two neutrons that are held together.
The beta particles are able to get stopped by a thin foil of aluminum is because of the fact that they are the charged particles and thus, associate electromagnetically more with the matter in comparison to the other kinds of radiations.