A staright wire of length `(pi^(2))` meter is carrying a current of `2A` and the magnetic field due to it is measured at a point distant `1 cm` from it. If the wire is to be bent into a circles and is to carry the same current as before, the ratio of the magnetic field at its centre to that obtained in the first case would be
A. `50:1`
B. `1:50`
C. `100:1`
D. `1:100`
