`M_n` and `M_p` represent mass of neutron and proton respectively. If an element having atomic mass `M` has `N-`neutron and `Z`-proton, then the correct relation will be :

Options

A. `M lt [NM_(n) + ZM_(p)]`
B. `M gt [NM_(n) + ZM_(p)]`
C. `M = [NM_(n) + ZM_(p)]`
D. `M = N [M_(n) + M_(p)]`

Answer

A

Explanation

Actual mass of the nucleus is always less than total mass of nucleons , so `M lt (N M_(n) + Z M_(p))`.