$\begin{array}{l}\text{Here, }\\ \text{By applying the rule of indices}\\ \text{we get,}\\ \\ {\text{= ? = (32)}}^{\text{20}}÷{\text{(32)}}^{\text{5}}\\ \\ {{\text{= ? = (32)}}^{\text{20}}}^{-\text{5}}{\text{= (32)}}^{\text{15}}\end{array}$

Hence, Option D is correct.