c
\((i)\) The \(+ I\) effect shown by methyl group increases the basic strength of the following compound.

\((ii)\) The \(+ M\) effect of \(- OCH _{3}\) group increases the basic strength of the following compound. \(+ M\) effect of \(- OCH _{3}\) is greater than \(+ I\) effect of \(- CH _{3}\)

\((iii)\) Among the given options, the following compound is the most basic as the \(- NH _{2}\) group does not involve in the resonance.

\((iv)\) Among the given options, the following compound is the least basic as - \(NH _{2}\) group is involved in the resonance.

Thus, the correct order of basic strength is

\(iii > ii > i > iv\)