Help i'm not sure which is correct
Alexander can earn money for the cans he recycles. Which of the following statements describes the variables in this situation correctly?

1: The number of cans recycled is the independent variable because it affects the amount of money earned.
2:The number of cans recycled is the dependent variable because it affects the amount of money earned.
3:The amount of money earned is the independent variable because it affects the number of cans recycled.
4:The amount of money earned is the dependent variable because it affects the number of cans recycled.