Answer:
The correct option is 4.
Step-by-step explanation:
If a graph passes vertical line test then the graph represents a function.
If graph of a function passes horizontal line test then inverse is also a function.
Vertical line test : There are no vertical lines, intersect the graph at more than one point.
Horizontal line test : There are no horizontal lines that intersect the graph at more than one point.
From the below graph it is clear that graph 1, 2 and 3 do not pass horizontal line test.
Only graph 4 passes the horizontal line test.
Therefore the correct option is 4.
