From a resistance to a molar conductivity

You will write three small functions. The first finds a cell constant from a calibration with potassium chloride. The second finds a conductivity. The third finds a molar conductivity. Then you use them on three solutions and pick the one with the largest molar conductivity.

The idea. $G^* = \kappa R$, then $\kappa = \dfrac{G^*}{R}$, and $\Lambda_m = \dfrac{10\,\kappa}{c}$ in $\text{S cm}^2/\text{mol}$ when $\kappa$ is in $\text{S/m}$ and $c$ is in $\text{mol/L}$.

Your tasks.

1. Complete cell_constant(r_kcl) so that it returns the cell constant in $\text{m}^{-1}$.
2. Complete conductivity(g_star, resistance) so that it returns $\kappa$ in $\text{S/m}$.
3. Complete molar_conductivity(kappa, c) so that it returns $\Lambda_m$ in $\text{S cm}^2/\text{mol}$.
4. Set best to the name of the solution with the largest molar conductivity.