11. Isabella drew two circles with radii of $2$ and $3$ on a piece of paper, and then drew the common tangents to these two circles, which turned out to be $k$ in number. Then, $k$ has ( ) possible scenarios.
(A) 2
(B) 3
(C) 4
(D) 5
(E) 6
11. D.

When two circles are concentric, $k=0$; when two circles are internally tangent, $k=1$; when two circles intersect, $k=2$; when two circles are externally tangent, $k=3$; when two circles are separated, $k=4$. Therefore, there are 5 possible values.