Sandra is buying new carpet for the floors of her house. The cost depends on the area of the floors. Which is the dependent variable, and which is the independent variable?

A. The dependent variable is the cost, and the independent variable is the area of the floors.
B. The dependent variable is the number of walls in the house, and the independent variable is the cost.
C. The dependent variable is the cost, and the independent variable is the number of walls in the house.
D. The dependent variable is the area of the floors, and the independent variable is the cost.​