$M_P$ 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 velocity of light )

Question

( A ) $M(NZ)=NM_{n}+ZM_p-B/c^{2}$
( B ) $M(NZ)=NM_{n}+ZM_p+B/c^{2}$
( C ) $M(NZ)=NM_{n}+ZM_p-B/c^{2}$
( D ) $M(NZ)=NM_{n}+ZM_p+B/c^{2}$