We have to find which of the relations given is a function.
The condition for a relation to be a function is that there is one and only one value in the range for each value in the domain.
Then, we can prove that a relation is not a function by finding a value in the domain that has two values in the range.
1) We have the relation: {(-3,0),(3,-1),(-3,1)}.
In this case, for x = -3 we have two values of y: y = 0 and y = 1.
Then, this relation does not satisfy the condition to be a function.
2) The relation {(4,-2),(2,13),(2,5)} is not a function as we have two values in the range for x = 2.
3) The relation {(-1,3),(-1,3),(3,3)} is not a function as we have two values in the range for x = -1.
4) The relation {(1,-3),(-2,0),(4,1)} is a function as there is one and only value of y for each x in the domain.
Answer: {(1,-3),(-2,0),(4,1)}