Concept:Use the properties of parallel lines and the angle sum of a triangle.Explanation:Since QR∥TU, the corresponding angles are equal.Therefore, ∠PTU=∠PQR=80∘.Points P, S, and T lie on a straight line, so angles on a straight line add up to 180∘.Given ∠PSU=95∘, it follows that ∠TSU=180∘−95∘=85∘.In triangle STU, the sum of interior angles is 180∘.Let x=∠SUT.Then x+80∘+85∘=180∘.So x=180∘−165∘=15∘.Answer:∠SUT=15∘, which is option A.
