Answer:
Graphs B and D
I can't see all the options since the image is cropped but it does look like the first option
Explanation:
A function, y = f(x0 can have one and only one value for a specific value of x
Graphically we can determine whether a graph represents a function or not by drawing a vertical line through a value of x and finding out if it intersects the graph at more than one point
Graph A: Not a function
If we draw a vertical line at say x = 0, it intersects the graph at two points y = 2 and y = -2. Therefore it is not a function
We need to see only one violation of this rule to conclude it is not a function
Graph B: Function
This is a function. There are 5 points plotted for 5 values of x (x = -5, -4, -1, 1 and 2) and at none of these values of x does a vertical line cross two points
Graph C Not a function
At x = 1, the vertical line will cross at 2 points (1, 5) and (1, -3). Essentially there are 2 y values, 5 and -3 for a single x value of 1
So not a function
Graph D Function
At no value of x does a vertical line pass through more than one point. Hence it is a function