4. In a Cartesian coordinate system, points $A$, $B$, and $C$ are not collinear. Now, with points $B$ and $C$ as foci, a hyperbola is drawn passing through $A$. With points $A$ and $B$ as foci, a hyperbola is drawn passing through $C$. With points $A$ and $C$ as foci, a hyperbola is drawn passing through $B$. Then, the number of common points of the three hyperbolas is ( ).
(A) 0
(B) 1
(C) 2
(D) Depending on the specific positions of $A$, $B$, and $C$, there are 1 or 2 points