An electrophile attacks the region of high electron density.
$-CH_3$ group, having $+I$ effect, increases the electron density in the benzene ring whereas $-Cl $ group having $-I$ effect decrease the electron density the benzene ring. Among,
I is deactivating due to $-I$ effect but $0 /P$ directing due $+M$ effect, where as II is deactivating due to $-I$ effect.
Hence (II) undergo electrophilic substitution reaction less readily than (I).
Therefore the decreasing order is Toluene > Benzene > Chlorbenzene > Anilinium chloride.
$IV > II > I > III$
Hence c is the correct answer.