A moving coil of a meter has 100 turns, and a length and depth of 10 mm and 20 mm respectively. It is positioned in a uniform radial flux density of 200 mT. the coil carries a current of 50 mA. The torque on the coil is

a)      200µNm

b)      100 µNm

c)       2 µNm

d)      1 µNm