AMC 10 2017b Problem 18

In the figure below, $3$ of the $6$ disks are to be painted blue, $2$ are to be painted red, and $1$ is to be painted green. Two paintings that can be obtained from one another by a rotation or a reflection of the entire figure are considered the same. How many different paintings are possible?

$\textbf{(A)}\ 6 \textbf{(B)}\ 8 \textbf{(C)}\ 9 \textbf{(D)}\ 12 \textbf{(E)}\ 15$