In the diagram, \triangle{PQR} is right-angled. Point S lies on PR so that \triangle{QRS} is equilateral and \triangle{PQS} is isosceles with PS=QS. The measure of \angle{QPR} is
Answer Choices
A. 35^\circ
B. 37.5^\circ
C. 25^\circ
D. 32.5^\circ
E. 30^\circ