If $X$ is specific resistance of electrolyte solution $Na_7SO_4$ and $y(N)$ is concentration of solution then $\Delta m$ is given by

Question

$\begin{array}{1 1}(a)\;\large\frac{1000}{XY}&(b)\;\large\frac{1000X}{Y}\\(c)\;\large\frac{XY}{1000}&(d)\;\large\frac{2000}{XY}\end{array}$