[单选题]
A proton is accelerated from rest typskkqmtl8mka ;xe0m53 --y7hrough 500.q2(p ndmg-, q y(rkpt(wbld 7 V. It enters a magnetic field of 0.30 T oriented perpendicular to its direction of motitmr .7nyw(-,k(g2 bd pqpq (ldon. Determine the radius of the path it follows.
A. $1.1 \; mm$
B. $1.1 \; cm$
C. $11 \; cm$
D. $1.1 \; m$