Given the relation R = { (−2, 3), (a, 4), (1, 9), (0, 7) }. Which replacement for a makes this relation a function?

The relation defined by the set of ordered pairs { (0, 2), (−2 ,2), (1, 4), (4, 1), (0, −1) } is not a function. Which of the ordered pairs listed below, if omitted from this relation, will make the resulting set a function?

The domain of this function is

{ (3,2), (−2 ,5), (-3, 1), (2, 1) }

The range of this function is

{ (3,2), (−2 ,5), (-3, 1), (2, 1) }

A mapping is shown in the diagram below.

This mapping is

Which graph represents a function?

Explanation must be included in the show your work box for full credit.