If \[x=a\sin \left( \omega t+\frac{\pi }{6} \right)\] and \[{x}'=a\cos \omega t\], then what is the phase difference between the two waves [RPET 1996]

• A.            p / 3                                         
• B.            p / 6
• C.            p / 2                                         
• D.            p