Read the following passage on the basis of your understanding of the following paragraph and the related studied concepts:
A freely suspended bar magnet capable of rotation in a horizontal plane in its equilibrium state, rests in the direction of earth's magnetic field at the place. If the magnet is slightly rotated from its equilibrium direction and then released, it executes angular oscillations of period T given as per relation
`T = 2pi sqrt((I)/(mB_H))`
Here I moment of inertia of bar magnet about its oscillation axis, magnetic moment of bar magnet and `B_H` horizontal component of earth's magnetic field at the place.
An oscillation magnetometer is designed on this principle and is employed to compare magnetic moments of magnets and for determining earth's magnetic field at a place.
The oscillation period of a given magnetic needle is 5 s at place A and 6 s at place B. The ratio of horizontal components of earth's magnetic field at A and B is

Options

A. `5/6`
B. `(36)/(25)`
C. `(12)/(5)`
D. `(6)/(5)`

Explanation

`((B_H)_A)/((B_H)_B) =((T_B)/(T_A))^2 = (6/5)^2 = (36)/(25)`