Which of the tables represents a function?

table a

Step-by-step explanation:

To be a function, every x has to have exactly one y. In table b the x value 5 has an output of 2 and 6 and therefore, since it has more than one y it is not a function. In table D the x value 6 has a y output of 7 and 2. Therefore it is not a function. In table A every x has exactly one y.