The order of the magnitude of first ionisation potentials of $Be$,$B$,$N$ and $O$ 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.

The incorrect statement among the following is:

Which of the following presents the correct order of second ionization enthalpies of $C$,$N$,$O$ and $F$?

The first ionisation energy of oxygen is less than that of nitrogen. Which of the following is the correct reason for this observation?

The first ionization enthalpy of $O$ is less than that of $N$,because .........