Ortho effect is special type of effect that is shown by o-subsituents .This ortho-effect operates at the benzoic acids irrespective of the polar type. Nearly all o-substituted benzoic acid are stronger than benzoic acid. Benzoic acid is a resonance stabilised and so the carboxyl group is coplaner with the ring. An o-subsituent tends to prevent this coplanarity.
Which among the following will be the strongest acid ?
A. I
B. II
C. III
D. IV
