The disintegration of an isotope of sodium,$_{11}Na^{24} \to _{12}Mg^{24} + _{-1}e^0$,shown is due to

• A
  The emission of $\beta$-radiation
• B
  The formation of a stable nuclide
• C
  The fall in the neutron $:$ proton ratio
• D
  All of the above