Which one of the following is the strongest base in aqueous solution ?

Q: Which one of the following is the strongest base in aqueous solution ?

d Aromatic amines are less basic than aliphatic amines. Among aliphatic amines the order of basicity is $2^{o}>1^{o}>3^{o} .$ The electron density is decreased in $3^{o}$ amine due to crowing of alkyl group over $N$ atom which makes the approach and bonding by a proton relatively difficult. Therefore the basicity decreases. Further Phenyl group show $- \,I$ effect, thus decreases the electron density on nitrogen atom and hence the basicity. $\therefore$ dimethylamine ( $2^{o}$ aliphatic amine) is strongest base among given choices. $\therefore$ The correct order of basic strength is Dimethyl amine $>$ Methyl amine $>$ Trimethyl-amine $>$ Aniline.