Answer:
Option A
Explanation:
According to Mulliken , electronegativity of an atom is average of ionization energy and electron affinity (in eV)
$n_{m}=\frac{IE+EA}{2}$
If ionization energy and electron affinity are in k cal mol-1
$n=\frac{IE+EA}{125}=\frac{275+86}{125}=2.88$