Himpunan berikut yang merupakan fungsi adalah ….
A. {(1, 1),(1, 2), (1, 3), (1, 4), (1, 5)}
B. {(1, 2),(2, 3), (3, 4), (4, 5), (5, 6)}
C. {(4, 2),(4, 3), (3, 1), (3, 2), (1, 1)}
D. {(4, 2),(3, 2), (2, 2), (2, 3), (1, 2)}
A. {(1, 1),(1, 2), (1, 3), (1, 4), (1, 5)}
B. {(1, 2),(2, 3), (3, 4), (4, 5), (5, 6)}
C. {(4, 2),(4, 3), (3, 1), (3, 2), (1, 1)}
D. {(4, 2),(3, 2), (2, 2), (2, 3), (1, 2)}