Magnetic field due to a ring having n turns at a distance `x` on its axis is proportional to (if `r =` radius of ring)

Options

A. `r/((x^(2)+r^(2)))`
B. `(r^(2))/((x^(2)_r^(2))^(3//2))`
C. `(nr^(2))/((x^(2)+r^(2))^(3//2))`
D. `(n^(2)r^(2))/((x^(2)+r^(2))^(3//2))`

Answer

C