Hybridization of ${\mathrm{PCl}}_5$ solid is :

The hybridization of PCL5 ions can be given as,.

$\begin{array}{cc}{\mathrm{PCl}}_4^{+}& {\mathrm{PCl}}_6^{-}\\ s{p}^3& s{p}^3{d}^2\end{array}$

therefore option a and b are shows correct hybridization.