Two particles are executing simple harmonic motion of the same amplitude A and frequency $\omega$ along the $x-axis$. Their mean position is separated by distance $X_0(X_0 > A)$. If the maximum separation between them is $(X_0+ A)$, the phase difference between their motion is :

Question

( A ) $\frac{\pi}{2}$
( B ) $\frac{\pi}{3}$
( C ) $\frac{\pi}{4}$
( D ) $\frac{\pi}{6}$