If $\sin x + \cos y = \large \frac{1}{3}$ and $\cos x + \sin y = \frac{1}{2}$, then $\tan \frac{(x-y)}{2}$

Question

$\begin{array}{1 1} -5 \\ -\frac{1}{5} \\ \frac {1}{5} \\ 5 \end{array}$