3. Let the left and right foci of the hyperbola be $F_{1}, F_{2}$, and the left and right vertices be $M, N$. If the vertex $P$ of $\triangle P F_{1} F_{2}$ is on the hyperbola, then the point where the incircle of $\triangle P F_{1} F_{2}$ touches the side $F_{1} F_{2}$ is
(A) inside the segment $M N$;
(B) inside the segment $F_{1} M$ or inside the segment $N F_{2}$;
(C) point $M$ or point $N$;
(D) cannot be determined.