1,2,3,6,   $P^{Kb}$ of amiline : 9.38, Ammonia – 4.75 

(i) and (ii) are less basic due to ortho effect.

(iii) is less basic due to aromaticity.

(vi) is less basic due to conjugation which occurs due to lone pair of electrons on nitrogen, the benzene ring and C=O groups.