Which element has the highest electronegativity?

Which of the following is most electronegative?

In $C$,$N$,$O$,and $F$,the electronegativity:

Given that the ionization potential and electron gain enthalpy of chlorine are $13 \ eV$ and $4 \ eV$ respectively. The electronegativity of chlorine on the Mulliken scale is approximately equal to: (in $eV$)

The polarity of a covalent bond between two atoms depends upon

Identify the most electronegative element among the following.