Answer:
A.
Explanation:
A ordered pair is when the x-axis of each point is different (only the x-axis)
Let's look at B
B has two x-axis point that is the same: (5,5) and (6,5)
Thus B is not a function
Let's look at C
C has two x-axis point that is the same: (2,3) and (2,6)
Thus C is not a function
Let's look at D
D has two x-axis point that is the same: (2,3) and (2,6)
Thus D is not a function
So A is the answer
Hope this helps!