Simplify : $\large\frac{4^{-3} \times a^{-5} \times b^{-4}}{4^{-5} \times a^{-8} \times b^3}$

Question

$\begin{array}{1 1} 16 \large\frac{a}{b} \\ 16\large\frac{a^3}{b} \\ 16\large\frac{a^3}{b^7} \\ 16 \large\frac{a^4}{b^4} \end{array} $