17・193 In $\triangle A B C$ (as shown in the figure) $\angle A B C=$ $60^{\circ}, \angle A C B=45^{\circ}$, and $A D, C F$ are both altitudes of the triangle, intersecting at $P$, while the angle bisector $B E$ of $\angle A B C$ intersects $A D, C F$ at $Q, S$. The number of isosceles triangles in the figure is
(A) 2.
(B) 3.
(C) 4.
(D) 5.
[Solution] It is easy to know that $\triangle Q A B, \triangle S B C, \triangle B A E, \triangle P Q S$ and $\triangle D A C$ are all isosceles triangles, a total of 5.

Therefore, the answer is $(D)$