In region of uniform magnetic induction B = 10-2 tesla, a circular coil of radius 30 cm and resistance `pi` ohm is rotated about an axis which is perpendicular to the direction of B and which forms a diameter of the coil. If the coil rotates at 200 rpm, the amplitude of the alternating current induced in the coil is
4`pi^2` mA
30 mA
6 mA
20 mA