Answer:
Sets A and B . choice D
Step-by-step explanation:
A relation from a set X to a set Y is said to be a function if each individual element of X is related to exactly one element in Y. In other words, given an element x contained in X, there is only one element in Y that x is related to.
Going by this definition, Sets A and B are functions since each element in x is related to exactly one element in y.
On the other hand, Set C is not a function since the element x = 2 has two corresponding y elements, 1 and 4