Concept:In a parallelogram, opposite angles are always equal in measure.Explanation:Given that PQRS is a parallelogram.In a parallelogram, each pair of opposite angles is equal.Hence, ∠P=∠R and ∠Q=∠S.Using ∠R=∠P in the given expression:∠P−∠R=∠P−∠P=0∘.So, the difference between the opposite angles ∠P and ∠R is 0∘.Therefore, the correct answer is option C.Answer:∠P−∠R=0∘Option C: 0∘