In the $xy$ plane, the line $l$ is perpendicular in the line described by the equation $\dfrac{1}{2x} + \dfrac{1}{y} = \dfrac{1}{2y}$, what is the slope of the line ?

Question

$\begin{array}{1 1} (a)\; -1 \\ (b)\; 1 \\ (c)\; \dfrac{1}{2} \\ (d)\; -\dfrac{1}{2} \end{array}$