A conductivity cell filled with 0.1 M KCl ($\kappa =1.29\mathrm{S}{\mathrm{m}}^{-1}$) has a resistance of $85\Omega$. When the same cell is filled with an unknown solution the resistance is $210\Omega$. The conductivity of the unknown solution is

1. A$0.522\mathrm{S}{\mathrm{m}}^{-1}$
2. B$3.19\mathrm{S}{\mathrm{m}}^{-1}$
3. C$1.92\mathrm{S}{\mathrm{m}}^{-1}$
4. D$6.14\times 10^{-3}\mathrm{S}{\mathrm{m}}^{-1}$