A body takes just twice the time as long to slide down a plane inclined at 30o to the horizontal as if the plane were frictionless. The coefficient of friction between the body and the plane is

(1) $\frac{\sqrt{3}}{4}$

(2) $\sqrt{3}$

(3) $\frac{4}{3}$

(4) $\frac{3}{4}$