Which ones are functions and which ones aren't?

Answer:
1. A is function.
2. A, is function
3. B is function.
Step-by-step explanation:
Hope it helps.
Answer:
1) B
2) A
3) B
Step-by-step explanation:
In a function... no value can be repeated in the domain
This is especially easy to discern in graphs because of the Horizontal Line Test