A bead of mass m stays at point P (a, b) on a wire bent in the shape of a parabola $y=4Cx^2$ and rotating with angular speed $\omega$ (see figure). The value of $\omega$ is (neglect friction)

(1) $\sqrt{2gC}$

(2) $\sqrt{2gC\over ab}$

(3) $\sqrt{2g\over C}$

(4) $2\sqrt{2gC}$