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 :

A

$$\Lambda_m - \Lambda^0_m + AC^{1/2} = 0$$

B

$$\Lambda^2_m C - K_a \Lambda^{\circ 2}_m + K_a \Lambda_m \Lambda_m = 0$$

C

$$\Lambda^2_m C + K_a \Lambda^{\circ 2}_m - K_a \Lambda_m \Lambda^\circ_m = 0$$

D

$$\Lambda_m - \Lambda^\circ_m - AC^{1/2} = 0$$