Answer
Choice C
Work Step by Step
Using the properties of radicals, the expression, $
\sqrt[]{8}
,$ simplifies to
\begin{array}{l}\require{cancel}
\sqrt[]{4\cdot2}
\\\\=
\sqrt[]{(2)^2\cdot2}
\\\\=
2\sqrt[]{2}
.\end{array}
Since this is not a whole number, then $\text{
Choice C
.}$