Force on Moving Charges: a Charge Is Accelerated from Rest

Force on moving charges: A charge is accelerated from rest through a potential difference V and then enters a uniform magnetic field oriented perpendicular to its path. The field deflects the particle into a circular arc of radius R. If the accelerating potential is tripled to 3V, what will be the radius of the circular arc?

A) 9R
B) 3R
C) R
D) R/
E) R/9