Which of the following two sets are equal?

• A. A = {1, 2} and B = {1}
• B. A = {1, 2} and B = {1, 2, 3}
• C. A = {1, 2, 3} and B = {2, 1, 3}
• D. A = {1, 2, 4} and B = {1, 2, 3}