$M_p$denotes the mass of a proton and $M_n$ that of a neutron. A given nucleus, of binding energy $B$, contains $Z$ protons and $N$ neutrons. The mass $M(N, Z)$ of the nucleus is given by ($c$ is the velocity of light)

• A

  $M(N,\mathrm{ }Z)=N{M}_n+Z{M}_p-B{c}^2$
• B

  $M\left(N,\mathrm{ }Z\right)=N{M}_n+Z{M}_p+B{c}^2$
• Correct answer
  C

  $M(N,\mathrm{ }Z)=N{M}_n+Z{M}_p-B/c^2$
• D

  $M\left(N,\mathrm{ }Z\right)=N{M}_n+Z{M}_p+B/c^2$

Hence, the correct answer is option: 'C'.