4. Given that $A$ and $B$ are two fixed points on a plane, and $AB=5$. If the distances from points $A$ and $B$ to line $l$ are $2$ and $3$ respectively, then the number of lines $l$ that satisfy the condition is ( ).
(A) 2
(B) 3
(C) 4
(D) infinitely many
4. (B).

The number of common tangents to two circles with centers at points $A$ and $B$ and radii 2 and 3, respectively, is the answer.