The displacement x (in metres) of a particle performing simple harmonic motion is related to time t (in seconds) as $\mathrm{x}=0.05\cos \left(4\mathrm{\pi }\mathrm{t}+\frac{\mathrm{\pi }}{4}\right)$ . The frequency of the motion will be 

• A

  0.5 Hz

• B

  1.0 Hz 

• C

  1.5 Hz

• D

  2.0 Hz