Answer:
Graph D
Explanation:
Graphs that represent functions have to correlate with each other in some way so it has to be either linear or non-linear so Graphs B and C are out of the question
To find the graph that represents a function you do the vertical line test which is when you draw a line though the x-axis and as soon as two or more points are on the same line it is no longer a function so graph a is out
By proess of elimination the function is graph D