If A = {1, 2, 3} and a relation R = {(1, 1), (1, 2), (2, 1), (2, 2), (3, 3)}, then R is:

If A = {1, 2, 3} and a relation R = {(1, 1), (1, 2), (2, 1), (2, 2), (3, 3)}, then R is:

• A. reflexive and symmetric only
• B. reflexive and transitive only
• C. symmetric and transitive only
• D. an equivalence relation

Answer: D) an equivalence relation

Explanation: All (a, a) are present → reflexive. (1, 2) and (2, 1) both present → symmetric. Transitive: (1, 2) and (2, 1) → (1, 1) ∈ R; (2, 1) and (1, 2) → (2, 2) ∈ R. So equivalence relation.