Diana can earn money for the tickets she sells. Which of the following statements describes the variables in this situation correctly?

The amount of money earned is the independent variable because it affects the number of tickets sold.
The amount of money earned is the dependent variable because it affects the number of tickets sold.
The number of tickets sold is the independent variable because it affects the amount of money earned.
The number of tickets sold is the dependent variable because it affects the amount of money earned.