Answer:
The mapping diagram above represents a function since there is one number in Set A (the input) where there is only one mapping to Set B (the output).
Step-by-step explanation:
For each number in set A, there is one mapping from set A (input) to set B (output), so the mapping represents a function.
NB. The relation is a function IF AND ONLY IF each input value has only 1 output value.
