Answer
$3 \sqrt[3]{2}$.
Work Step by Step
Factor the radicand so that one fo the factors is a perfect cube number.
$\sqrt[3]{54}=\sqrt[3]{27\cdot 2}$
Use $27=3^3$.
$=\sqrt[3]{3^3\cdot 2}$
Separate cube roots using the rule $\sqrt[n]{xy}=\sqrt[n]{x}\cdot\sqrt[n]{y}, x, y>0$ to obtain:.
$=\sqrt[3]{3^3}\cdot \sqrt[3]{2}$
Simplify.
$=3 \sqrt[3]{2}$
Hence, the correct answer is $3 \sqrt[3]{2}$.
