Answer: Option (b) is the correct answer.
Explanation:
A positively charged particle that consists of two protons and two neutrons is known as an alpha particle.
The symbol for alpha particle is [tex]^{4}_{2}\alpha[/tex]. An alpha particle is similar to a helium atom because helium atom also has mass number (number of protons + number of neutrons) as 4 and atomic number (number of protons) as 2.
Symbol of helium atom is [tex]^{4}_{2}He[/tex].
Thus, we can conclude that an alpha particle is also referred to as a nucleus of helium isotope.
