we are given four relation graph and we want to find which is a function
Solution
Use the vertical line test to determine whether or not a graph represents a function. If a vertical line is moved across the graph and, at any time, touches the graph at only one point, then the graph is a function. If the vertical line touches the graph at more than one point, then the graph is not a function.
For Option B
That is a circle graph
It is not a function because, when we draw a vertical line, the line will touch the graph at more than one point
For Option C
It is not a function because, when we draw a vertical line, the line will touch the graph at more than one point
For Option A
It is not a function because, when we draw a vertical line on the line of option A it touches the graph every point
For Option D
This is a function by the vertical line test, The vertical line only touch the graph at one point
The answer is the graph above
