Which of the following statements is not correct?

(a) The adjacent$\mathrm{C}=\mathrm{O}$ weakens the basicity by delocalisation of electron density from $\mathrm{N} \mathrm{to} \mathrm{O}$.

(b) The ability of $\mathrm{C}=\mathrm{O}$ to cause base-weakening is attenuated by the phenyl group, making benzamide a stronger base than acetamide

(c) Phenyl group has a base-weakening effect because of its ability to form extended p-bonding between the amino N and the phenyl ring

In the structure$\mathrm{II}$,$\mathrm{N}-\mathrm{H}$ bonds are in the plane of benzene ring. In 2,$\text{ 6-dimethyl- }N,N\text{-dimethylaniline, }$the formation of extended$\mathrm{\pi }$-bonding is sterically hindered and thus interfere with the base-weakening extended $\mathrm{\pi }$-bonding making this compound much more basic than 2, 6-dimethylaniline.

( d) The nitro group is more effective than cyano group in weakening the basic nature of aniline.

In nitroaniline, electron delocalisation ends up with the negative charge on the more electronegative oxygen atom whereas in cyanoaniline, the negative charge ends up in the nitrogen atom (which is less electronegative than oxygen).