What is the Cartesian product of A = {1, 2} and B = {a, b}?

• A. {(1, a), (1, b), (2, a), (b, b)}
• B. {(1, 1), (2, 2), (a, a), (b, b)}
• C. {(1, a), (2, a), (1, b), (2, b)}
• D. {(1, 1), (a, a), (2, a), (1, b)}