The self-induced e.m.f. in a 0.1 H coil when the current in it is changing at the rate of 200 A/s is

• A

  $8\times {10}^{-4} \mathrm{V}$

• B

  $8\times {10}^{-5} \mathrm{V}$

• C

  20 V

• D

  125 V