Ionization energy increases in the order

The electronic configurations of elements $A, B$ and $C$ are $[He] 2s^1$,$[Ne] 3s^1$ and $[Ar] 4s^1$ respectively. Which one of the following orders is correct for the first ionization potentials (in $kJ \ mol^{-1}$) of $A, B$ and $C$?

Consider the elements $Ne$,$Na$,and $Mg$. The element with the highest first ionization enthalpy and the element with the lowest second ionization enthalpy,respectively,are:

Among the following,which has the highest first ionization energy?

Find the formula of the halide of a metal whose successive ionization energies are $10, 16, 25, 400, 500 \ eV \ mol^{-1}$ respectively $:-$

Which one of the following elements has the highest ionisation energy?