#### Answer

Choice D

#### Work Step by Step

Using the Power Rule of the laws of exponents which is given by $\left( x^m \right)^p=x^{mp},$ then
\begin{array}{l}\require{cancel}
\left( x^{1/5} \right)^{5/2}
\\\\=
x^{\frac{1}{5}\cdot\frac{5}{2}}
\\\\=
x^{\frac{1}{2}}
\\\\=
x^{1/2}
.\end{array}
Hence, $\text{
Choice D
.}$