A Particle with a Charge of 1 $\times$ 10^-19 and a Mass of 1

Multiple Choice

A particle with a charge of 1.60 $\times$ 10^-19 and a mass of 1.67 $\times$ 10^-27 kg is found moving in a uniform magnetic field of a strength 1.50 T. The trajectory of the particle is perpendicular to the magnetic field and is circular with a radius of 1.80 cm. The cyclotron frequency is

A) 14 MHz.
B) 23 MHz.
C) 27 MHz.
D) 27 Hz.