Molar conductances of $BaCl_2, H_2SO_4\: and HCl$ at infinite dilution are $X_1,X_2\: and \: X_3$ respectively. Molar conductance of $ BaSO_4$ at infinite dilusion is

Question

$\begin {array} {1 1} (1)\;(X_1+X_2-2X_3)/2 & \quad (2)\;X_1+X_2-X_3 \\ (3)\;X_1+X_2-2X_3 & \quad (4)\;(X_1+X_2-2X_3)/2 \end {array}$