Answer:
A
Explanation:
Recall that for a function to be valid, each input value of x must give us one and only one unique output value for y.
in this case we can see that one of the data sets is (3,-1)
which means that an input of 3 gave an output of -1
but we also see that another data set (3,1)
in this case an input of 3 gave an output of 1.
Because the same x input gives 2 different y outputs, this is not a function.
the answer is A