A charged particle having drift velocity of $7.5\times {10}^{-4}\mathrm{m}{\mathrm{s}}^{-1}$ in an electric field of $3\times {10}^{-10}{\mathrm{Vm}}^{-1},$ has a mobility in ${\mathrm{m}}^2{\mathrm{V}}^{-1}{\mathrm{s}}^{-1}$ of

• A

  $2.5\times {10}^6$

• B

  $2.5\times {10}^{-6}$

• C

  $2.25\times {10}^{-15}$

• D

  $2.25\times {10}^{15}$