The following points represent a relation where x represents the independent variable and y represents the dependent variable.

three fourths comma negative 2, 1 comma 5, negative 2 comma negative 7, 1 comma negative one half, and 6 comma 6

Does the relation represent a function? Explain.

No, because for each input there is not exactly one output
No, because for each output there is not exactly one input
Yes, because for each input there is exactly one output
Yes, because for each output there is exactly one input