A cylinder, cone and a sphere are of the same radius and same height. Find the ratio of their curved surface areas.

Question

$\begin{array}{1 1} (a)\; 1 : \sqrt{5}:1 \\ (b)\; 2:\sqrt{5}:2 \\ (c)\; 1:\sqrt{5}:4 \\ (d)\; 4:\sqrt{5}:4 \end{array}$