Two similar coils are kept mutually perpendicular such that their centres coinside. At the centre, find the ratio of the mag. field due to one coil and the resultant magnetic field by both coils, if the same current is flown.
Options:
(a) 1 : `sqrt2`
(b) 1 : 2
(c) 2 : 1
(d) `sqrt3` : 1