Susan uses the function p(x) = 4x to determine the perimeter of a square when she knows the side length, x. Which statements are true about the function?

The length of the side of the square is the dependent variable.

The perimeter is the dependent variable.

The value of p(x) depends on the value of x.

The value p(x) can be found by multiplying p by x.

The length of the side of the square is the independent variable.

The perimeter is the independent variable.