The $B-H$ curve for a ferromagnet is shown in the figure. The ferromagnet is placed inside a long solenoid with $1000 \mathrm{turns} {\mathrm{cm}}^{-1}$. The current that should be passed in the solenoid to demagnetize the ferromagnet completely is, 

• A

  $2 \mathrm{mA}$
• B

  $20 \mathrm{\mu A}$
• Correct answer
  C

  $1 \mathrm{mA}$
• D

  $40 \mathrm{\mu A}$

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