$M_n$ 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

$M<\left[N M_n+Z M_P\right]$ $M>\left[N M_n+Z M_P\right]$ $M=\left[N M_n+Z M_P\right]$ $M=N\left[M_n+M_P\right]$

$M<\left[N M_n+Z M_P\right]$

Actual mass of the nucleus is always less than total mass of nucleons so $M<\left[N M_n+Z M_P\right]$.