SOLUTION:
In the given question, we are asked to find which one of the given function is true using the set of ordered pairs.
For a function f(x), the value of x gives the x-value of the ordered pair while f
1.

This is FALSE, from the function rule;

2.

This is FALSE, from the function rule;

3.

This is TRUE, from the function rule
4.

This is also FALSE.
Thus the answer is C