On the set A = {1, 2, 3}, a relation R = {(1, 2), (2, 1)} is defined. R is:

On the set A = {1, 2, 3}, a relation R = {(1, 2), (2, 1)} is defined. R is:

• A. Reflexive and symmetric
• B. Symmetric but neither reflexive nor transitive
• C. Transitive and symmetric
• D. An equivalence relation

Answer: B) Symmetric but neither reflexive nor transitive

Explanation: It lacks (1,1), (2,2), etc., so it's not reflexive. It has (1,2) and (2,1), so it's symmetric. It lacks (1,1) which would be required for transitivity since (1,2) and (2,1) are in R. So, not transitive.