Answer:
Option A. Graph D only
Explanation:
A function is an output of the mapping of the values of x into the output y.
In other words, the function is given by the expression:
y = f(x)
Let's look at the graphs in turn:
The graph A gives straight line equations, however, we cannot interpret these in terms of a definite function.
The graph B is a series of dots. It is not a function.
The C is a series of dots. It is not a function.
The graph D only is a function. It is a reflection about the x- axis.