A liquid is kept in a cylindrical vessel which is being rotated about a vertical axis through the centre of the circular base. If the radius of the vessel is r and angular velocity of rotation is \[\omega \], then the difference in the heights of the liquid at the centre of the vessel and the edge is

• A.             \[\frac{r\omega }{2g}\]    
• B.             \[\frac{{{r}^{2}}{{\omega }^{2}}}{2g}\]
• C.             \[\sqrt{2gr\omega }\]       
• D.              \[\frac{{{\omega }^{2}}}{2g{{r}^{2}}}\]