Two Singly Ionized Isotopes,X and Y,of the Same Element Move

Two singly ionized isotopes,X and Y,of the same element move with the same speed perpendicular to a uniform magnetic field.Isotope X follows a path of radius 3.35 cm while isotope Y moves along a path 3.43 cm in radius.What is the ratio of the two isotope masses,m_X/m_Y?

A) 0.977
B) 1.02
C) 1.05
D) 0.954