If $w=\dfrac{1}{8} $ then which of the following is equal to $w^{\large\frac{2}{3}} ?$

Question

$\begin{array}{1 1} (a)\;\dfrac{1}{16} \\ (b)\; \dfrac{1}{64} \\ (c)\; \dfrac{1}{4} \\ (d)\; \dfrac{1}{2} \end{array}$