d
(d) With emission of an \(\alpha \) particle \({(_2}H{e^4})\) mass number decreases by \(4 \) unit and atomic number decrease by \(2\) units and with emission of \(2{\beta ^{ - 1}}\) particle atomic number increases by \(2\) units.

So \( Z\) will remain same and \(N\) will become \(N - 4.\)