Two particles `X` and `Y` with equal charges, after being accelerated throuhg the same potential difference, enter a region of uniform magnetic field and describe circular paths of radii `R_(1)` and `R_(2)` respectively. The ratio of the mass of `X` to that of `Y` is
A. `R_(1) //R_(2)`
B. `(R_(1)//R_(2))^(2)`
C. `(R_(2)//R_(1))`
D. `(R_(2)//R_(2))^(2)`