Answer:
Option 4
Explained below
Explanation:
A relationship is a function if and only if one value of the input does not result in more than one value of the output
In other words, for a function f(x), for a value of x there should only be one value for y
Looking at the figure, we see that in option 4 for the value 2 there are two resultant mappings, A and B
Hence the relation in option 4 is NOT a function