Force on Moving Charges: Ions Having Equal Charges but Masses

Force on moving charges: Ions having equal charges but masses of M and 2M are accelerated through the same potential difference and then enter a uniform magnetic field perpendicular to their path. If the heavier ions follow a circular arc of radius R, what is the radius of the arc followed by the lighter?

A) 4R
B) 3R
C) R
D) R/
E) R/2