Let A = \{1, 2, 3, 4\}, B = \{1, 5, 9, 11, 15, 16\} and f = \{(1, 5), (2, 9), (3, 1), (4, 5), (2, 11)\}. Are the following true? (i) f is a relation from A to B (ii) f is a function from A to B. Justify your answer in each case.