The magnetic field in the cylindrical region shown in figure increases at a constant rate of 20 mT/s. Each side of the square loop ABCD has a length of 1 cm and resistance of $4 \mathrm{\Omega }.$ Find the current in the wire AB if the switch S is closed

• A

  $1.25\times {10}^{-7}\mathrm{A}\text{ (anticlockwise) }$

• B

  $1.25\times {10}^{-7}\mathrm{A} \text{ (clockwise) }$

• C

  $2.5\times {10}^{-7}\mathrm{A}\text{ (anticlockwise) }$

• D

  $2.5\times {10}^{-7}\mathrm{A}\text{ (clockwise) }$