(b)
$C_{6}H_{5}CH_{3}\overset{Oxidation\ \ }{\rightarrow}C_{6}H_{5}.COOH\overset{NaOH\ \ }{\rightarrow}$
$(A)$
$C_{6}H_{5}COONa\overset{\begin{array}{r}
Soda\ lime \\
(NaOH + CaO)
\end{array}}{\rightarrow}C_{6}H_{6} + CO_{2} \uparrow$
$\ \ \ \ \ \ \ \ \ \ (B)$