Which out of the following is a correct equation to show change in molar conductivity with respect to concentration for a weak electrolyte, if the symbols carry their usual meaning:
\( \Lambda_{m}-\Lambda_{m}^{\circ}-A\,C ^{\frac{1}{2}}=0 \)
\( \Lambda_{m}^{2}C+K_{a}\Lambda_{m}^{\circ\,2}-K_{a}\Lambda_{m}\Lambda^{\circ}{m}=0 \)
\( \Lambda_{m}-\Lambda_{m}^{\circ}+A\,C^{\frac{1}{2}}=0 \)
\( \Lambda_{m}^{2}C-K_{a}\Lambda_{m}^{\circ\,2}+K_{a}\Lambda_{m}\Lambda_{m}^{\circ}=0 \)