The mapping diagram shows a function S(x).
Which mapping diagram shows the inverse of S(x)?

Explanation:
Notice how the input 5 leads to the output 3 when we look at the S(x) function. The inverse will undo this. So that must mean the answer is choice A where we have the input 3 lead to the output 5. In short, the inputs and outputs swap places. This means the domain and ranges swap.