$29.$If the viscosity of aqueous solution is $8\mathrm{.}94{10}^{-4}Pa.s,$ and the radius of $C{a}^{2+}$ ion is $308pm.$ The mobility $(\frac{m^2}{s}.V)$ of $C{a}^{2+}$ ion in water is

$2\mathrm{.}17{10}^{-8}$

$5\mathrm{.}19{10}^{-8}$

$6\mathrm{.}17{10}^{-8}$

$6\mathrm{.}17$