In the diagram shown, PQ=SQ=QRPQ = SQ = QRPQ=SQ=QR and ∠SPQ=2×∠RSQ\angle SPQ = 2 \times \angle RSQ∠SPQ=2×∠RSQ. What is the size of angle QRSQRSQRS?(A) 20∘20^\circ20∘ (B) 25∘25^\circ25∘ (C) 30∘30^\circ30∘ (D) 35∘35^\circ35∘ (E) 40∘40^\circ40∘