Which of the following is not correct ?

Options

A. The outermost electronic configuration of most electronegative elements is `ns^2ns^5`
B. Order of size: `O^(2-)gtF^-gtNa^(+)gtMg^(2+)gtAl^(3+)`
C. Conjugate acid/base pair: `HCO_3^(-)//CO_3^(2-)`
D. Inert pair effect causes increase in oxidation state of element