Two discs of radius 2 cm and 1 cm, made of the same material are placed as shown . The center of mass from $O_1$ is:

Question

$\begin {array} {1 1} (a)\;0.4\;cm \\ (b)\;1.5\;cm \\ (c)\;0.6\;cm \\ (d)\;0.8\;cm \end {array}$