Explanation

(d)
$CH_{3} -$ (an electron releasing (+I )group) increases electron density at N-atom hence, basic nature is increased.
[image:13_image184.emf] [image:13_image185.emf] [image:13_image186.emf]
[image:13_image187.emf]
$C_{6}H_{5}$ decreases electron density at N-atom thus basic nature is decreased. (Lone-pair on N in aniline compounds is delocalised along with $\pi$-electrons in benzene).
Thus, (d) is the strongest base.