Answer
Choice D
Work Step by Step
Since $\sqrt[3]{125}=5$, the expression, $
\dfrac{\sqrt[3]{10}}{5}
$ (Choice D), is equivalent to
\begin{align*}
&
\dfrac{\sqrt[3]{10}}{\sqrt[3]{125}}
.\end{align*}
Since $\dfrac{\sqrt[n]{a}}{\sqrt[n]{b}}=\sqrt[n]{\dfrac{a}{b}}$, then the expression above is equivalent to
\begin{align*}\require{cancel}
&
\sqrt[3]{\dfrac{10}{125}}
\\\\&=
\sqrt[3]{\dfrac{\cancelto2{10}}{\cancelto{25}{125}}}
&(\text{divide by }5)
\\\\&=
\sqrt[3]{\dfrac{2}{25}}
.\end{align*}
Since $\sqrt[3]{\dfrac{2}{25}}\ne\sqrt[3]{\dfrac{2}{5}}$, then the expression that is not equal to $\sqrt[3]{\dfrac{2}{5}}$ is Choice D.