The velocity distribution in the boundary layer is given as $\frac{U}{U_{\infty }}$, where u is the velocity at a distance y from the boundary, $U_{\infty }$ is the free stream velocity and $\delta$ is the boundary layer thickness certain distance from the leading edge of plate. The of displacement thickness to momentum thickness is
(a) 5 (b) 4
(c) 3 (d) 2