#### Answer

One-to-one
The elements of the inverse of this function are as follows in the form $(Input, Output)$:
$(4, Northeast), (3, Midwest), (1, South), (2, West)$

#### Work Step by Step

A function is one-to-one if each x-value (input) corresponds to only one y-value (output) and also each y-value (output) corresponds to only one x-value (input).
This function is one-to-one, because each input corresponds to only one output, and vice versa. To find the elements of its inverse, we interchange the input and output of each point.
Therefore, the elements of the inverse of this function are as follows in the form $(Input, Output)$:
$(4, Northeast), (3, Midwest), (1, South), (2, West)$