Answer:
The correct option is 1.
Explanation:
A relation is called a function if there exist one value of y for each value of x.
In a mapping first set represent the value of x and second set represent the value of y.
In mapping 1, for
, the value of y is -4 and 3. For single of x there exist more than one value of y, therefore this relation is not a function.
In mapping 2 and 3, for all values of x, the value of y is unique. For single of x there exist only one value of y, therefore these relations are function.
Therefore mapping 1 does not represent a function. Option 1 is correct.