Correct Answer - B
(b) Beta decay can involve the emission of either electrons or positrons. The electrons or positrons emitted in a `beta-decay` do not exist inside the nucleus. They are only created at the time of emission. Just as photons are created when an atom makes transition from higher to a lower energy state.
In negative `beta-decay` a neutron in the nucleus is transformed into a proton, an electron and an antineutrino. Hence, in radioactive decay process, the negatively charged emitted `beta-`particles are the electrons produced as a result of the decay of neutrons present the nucleus.
