Answer:
Option D
Explanation:
Set of data in terms of ordered pairs represents a function when output value of each input value is different.
Option A
Since, for every value of x there is a different value of y, it's a function.
Option B
In each ordered pair, for every value of x there is a different value of y.
Therefore, it's a function.
Option C
From the given graph, for every value of x there is a different value of y.
Therefore, it's a function.
Option D
From the given set of ordered pairs we find for x = 1 there are two values of y (y = 4 and 3).
Therefore, the given set of ordered pairs doesn't represent a function.
Option D is the answer.