Solve qus no. 16:

16. A compass needle of magnetic moment 60A-m^​2, pointing geographic north at a place where the horizontal component of earth's magnetic field is 40 x 10^-6 WB/m² experiences  a torque of 1.2 x 10^-3 N-m. the Declination of the place is.

(a) 15^o        (b) 45^o
(c) 30^o        (d) none of these.