Answer:
The 4th table represents a function.
Explanation:
A function only gives one unique output for every unique. This means a function f(5) cannot output 6 or 8; it can output only one of these two values.
Looking at the 1st table we see that y(1) gives 1,2,3,4, and 5: it gives 5 outputs for a single input; therefore, this table cannot represent a function.
The 2nd Table gives three outputs for y(3); this cannot represent a function.
The 3rd table gives two outputs for y(-1): this also cannot be a function.
The 4th table gives a unique output for every unique output for every unique input; therefore, this table represents a function.