A long solenoid has $70 \mathrm{turns} {\mathrm{cm}}^{-1}$ and carries current $I$. An electron moves within the solenoid in a circle of radius $2.5 \mathrm{cm}$ perpendicular to the solenoid axis. If the speed of the electron is $4.4\times {10}^6 \mathrm{m} {\mathrm{s}}^{-1}$ then the current $I$ in the solenoid is
(Take ${\mu }_0=4\pi \times {10}^{-7}\mathrm{SI}$ unit, mass of electron $=9\times {10}^{-31} \mathrm{kg}$, charge of electron $=1.6\times {10}^{-19}\mathrm{C}$)

• A

  $98.5 \mathrm{mA}$
• Correct answer
  B

  $112.5 \mathrm{mA}$
• C

  $125 \mathrm{mA}$
• D

  $175.0 \mathrm{mA}$

Hence, the correct answer is option: 'B'.