Which option is correct?

Carbon has a higher third ionization energy than nitrogen. The identical electrons, the $1{\mathrm{s}}^{2}2{\mathrm{s}}^2$ electrons, are used to protect both materials, although nitrogen has a larger nuclear charge.

The oxygen has a higher second ionization energy than nitrogen. The oxygen ion (O+) achieves a half-filled electronic state and becomes more stable when second ionization energy is taken into account. O thus has a higher second ionization energy than nitrogen.

All option is correct as,

2nd I.E. of N < O, 

3rd I.E. of C > N 

1st I.E. of F > O