\((8a^{-3})^\frac{2}{3}=(8 \cdot \frac{1}{a^3})^\frac{2}{3}=(\frac{8}{a^3})^\frac{2}{3}=\sqrt[3]{(\frac{8}{a^3})^2}=\sqrt[3]{\frac{64}{a^6}}=\frac{\sqrt[3]{64}}{\sqrt[3]{a^6}}=\frac{4}{a^2}\)
It doesn't equal any of the answers A, B, C.
The answer is D.
