An Electron Follows a Circular Path (Radius = 15 Cm)in $\mu$

Multiple Choice

An electron follows a circular path (radius = 15 cm) in a uniform magnetic field (magnitude = 3.0 G) .What is the period of this motion?

A) 0.12 $\mu$ s
B) 1.2 ms
C) 0.18 $\mu$ s
D) 1.8 ms
E) 1.8 $\mu$ s