Which of the following statement is correct?

A. The periodic time of a particle moving with simple harmonic motion is the time taken by a particle for one complete oscillation.

B. The periodic time of a particle moving with simple harmonic motion is directly proportional to its angular velocity.

C. The velocity of a particle moving with simple harmonic motion is zero at the mean position.

D. The acceleration of the particle moving with simple harmonic motion is maximum at the mean position.