A Proton Has a Speed of 3

A proton has a speed of 3.0 × 10⁶ m/s in a direction perpendicular to a uniform magnetic field, and the proton moves in a circle of radius 0.20 m. What is the magnitude of the magnetic field?

A) 0.040 T
B) 0.080 T
C) 0.16 T
D) 0.24 T
E) 0.32 T