[单选题]
A proton is accelerated from q8 bs7k db-kuhr96zb)vd y5i )rest through 500 V. It enters a magnetic field ofr;0ofyj; pzq8 0.30 T oriented perpendicular to its direction qo8;yp fz j0;rof motion. Determine the radius of the path it follows.
A. $1.1 \; mm$
B. $1.1 \; cm$
C. $11 \; cm$
D. $1.1 \; m$
