A magnet oscillating in a horizontal plane has a time period of 2 seconds at a place where the angle of dip is `30^(@)` and 3 seconds at another place where the angle of dip is `60^(@)`. The retio of resultant magnetic field at the two places is
A. `(4sqrt(3))/(7)`
B. `(4)/(9sqrt(3))`
C. `(9)/(4sqrt(3))`
D. `(9)/(sqrt(3))`