The displacement of a particle executing simple harmonic motion is given by
$$y = A_0 + A \sin \omega t + B \cos \omega t$$
Then the amplitude of its oscillation is given by:

A

$$\sqrt {A^2 + B^2} $$

B

$$\sqrt {A_0^2 + (A +B)^2}$$

C

$$A + B$$

D

$$A_0 + \sqrt {A^2 + B^2} $$