Let A={1,2} and B={3,4}. Which of the following cannot be relation from set A to set B?

• A. {(1,1), (1,2), (1,3), (1,4)}
• B. {(1,3), (1,4)}
• C. {(2,3), (2,4)}
• D. {(1,3), (1,4), (2,3), (2,4)}