Statement (A): The first ionization energy of Al is less than the first ionization energy of Mg. 

Statement (B): The first ionization energy of Na is less than the first ionization energy of Mg. 

Statement (C): The second ionization of Mg is greater than the second ionization energy of Na.

 “Al” contains one unpaired electron remove the electron easy less amount of energy. “Na” contain unpaired electron remove electron less amount of energy required.

$\mathrm{Al}=\left[\mathrm{Ne}\right]3{\mathrm{s}}^{2}3{\mathrm{p}}^1, \mathrm{Mg}=\left[\mathrm{Ne}\right]3{\mathrm{s}}^2, \mathrm{Na}=\left[\mathrm{Ne}\right]3{\mathrm{s}}^1$

Mg is a stable electronic configuration we remove the electron more amount of required compare to Al and Na.