Simplify $(64a^3 \div 27 b^{-3} )^{\large\frac{-2}{3}}$

Question

$\begin{array}{1 1} \large\frac{9}{16} \\ \large\frac{9}{16a^2b^2} \\ \large\frac{9b^2}{16a^2} \\ \large\frac{9b^2}{a^2} \end{array} $