Answer:
A
Step-by-step explanation:
Each domain value (x-value) of a function has exactly one range value (y-value).
A function can have two or more domain (x-value) having the same range (y-value)
Graph A shows the different domain value (x-values) having exactly one range value (y-value). No x-value has two different y-values.
Therefore, graph A is a function.
