$A$ nucleus of an element ${}_{84}X^{202}$ emits an $\alpha$-particle first,a $\beta$-particle next,and then a gamma photon. The final nucleus formed has an atomic number:

$A$ nucleus of lead $Pb_{82}^{214}$ emits two electrons followed by an $\alpha$-particle. The resulting nucleus will have

Beta rays emitted by a radioactive material are

$A$ free neutron decays into a proton, an electron and

$A$ free neutron decays spontaneously into :

Originally, radioactive beta decay was thought to be a decay of a nucleus with the emission of electrons only (Case $I$). However, in addition to the electron, another (nearly) massless and electrically neutral particle is also emitted (Case $II$). Based on the figure below, which of the following is correct?