In a group $\frac{5}{9}$ of the members are boys. What is the ratio of girls to boys in the group ?

Question

$\begin{array}{1 1} (a)\; \frac{4}{9} \\ (b)\; \frac{5}{9} \\ (c)\; \frac{4}{5} \\ (d)\; \frac{5}{4} \end{array}$