The first ionization enthalpies of Be, B, N and O follow the order

The IUPAC nomenclature of an element with electronic configuration [Rn] $$5 \mathrm{f}^{14} 6 \mathrm{d}^{1} 7 \mathrm{s}^{2}$$ is :

The correct order of electron gain enthalpy ($$-$$ ve value) is :

Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : The first ionization enthalpy for oxygen is lower than that of nitrogen.

Reason R : The four electrons in 2p orbitals of oxygen experience more electron-electron repulsion.

In the light of the above statements, choose the correct answer from the options given below.