Concept:Use alternate interior angles and the angle sum on a straight line.Explanation:Since PQ∥RS and EG is a transversal, alternate interior angles are equal.So, ∠EGR=∠FEG=50∘.On line PQ, ∠QFG and ∠EFG form a linear pair.Thus, ∠EFG=180∘−105∘=75∘.In △EFG, the sum of angles is 180∘.So, ∠FGE=180∘−50∘−75∘=55∘.At point G, angles on the straight line RGS add up to 180∘.Therefore, n+55∘+50∘=180∘.Hence, n=180∘−105∘=75∘.Answer:n=75∘, which is Option C.