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

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

$\Lambda=\bigg(\large\frac{1000.K}{C}\bigg)$-------(I)
$K=\large\frac{1}{\rho}$
$N=\eta M$
N-normality
M-Molarity
$\eta$-n factor
$M=\large\frac{Y}{2}$
Put in (I) we get
$\Lambda_m=\large\frac{1000\times 2}{XY}$
$\quad\;\;\;=\large\frac{2000}{XY}$
Hence (d) is the correct answer.