If $a=2$ and $b=3$ , then the value of $\bigg( \large\frac{1}{a} +\frac{1}{b}\bigg)^a$=_____

Question

$\begin{array}{1 1} \large\frac{5}{6} \\ \large\frac{25}{36} \\ \large\frac{125}{216} \\ none\;of\;the\;above \end{array}$