Julio works as a Salesman. He receives a monthly salary of 3000 as well as 10% commission on the amount of sale. What is the independent variable and the dependent variable?

a. Independent variable: Monthly salary, Dependent variable: Commission
b. Independent variable: Commission, Dependent variable: Monthly salary
c. Independent variable: Monthly salary, Dependent variable: Total earnings
d. Independent variable: Total earnings, Dependent variable: Monthly salary