Which of the following relations is symmetric and transitive but not reflexive for the set I = {4, 5}?

• A. R = {(4, 4), (5, 4), (5, 5)}
• B. R = {(4, 4), (5, 5)}
• C. R = {(4, 5), (5, 4)}
• D. R = {(4, 5), (5, 4), (4, 4)}