Amines Part 1

In phenyl methanamine, the lone pair on nitrogen of −NH2 group is localised and does not undergoes resonance as attached to sp3-hybridised C-atom.
Phenyl methanamine or benzyl amine(B),(C) and (D) are aromatic amines in which lone pair of electrons of N-atoms goes in resonance
(+ R effect) with the benzene ring. So, Lewis basicity or donation of lone of electrons of these amines will be decreased in comparison to (A).+I effects of two −CH3 groups are in compensation with −R effect of the ring.+ l effect of one −CH3 group is trying to compensate −R effect of the ring.It has no + leffect on N-atom to outweigh −R-effect of the ring.
So, A is purely aliphatic 1∘-amine. B is aromatic 3∘-amine with more aliphatic nature (for two −CH3 groups). C is aromatic 2∘-amine with less aliphatic nature (for one −CH3 group).
D is purely aromatic 1∘-amine. Hence basicity order is A>B>C>D.