Resistance of a conductivity cell filled with a solution of an electrolyte of concentration $0.1\; M$ is $100\; \Omega$. The conductivity of this solution is $1.29\; S\; m^{-1}$. Resistance of the same cell when filled with $0.2\; M$ of the same solution is $520 \Omega$. The molar conductivity of $0.02 \; M$ solution of the electrolyte will be :

Question

( A ) $1.24 \times 10^{-4} S\; m^2 \; mol^{-1}$
( B ) $12.4 \times 10^{-4} S\; m^2 \; mol^{-1}$
( C ) $124 \times 10^{-4} S \; m^2 mol^{-1}$
( D ) $1240 \times 10^{-4} S\; m^2 \; mol^{-1}$