A rectangular box with a square base, and a volume of 216 in³ is to be constructed. Suppose the cost of the material for the base is 30¢/square inch, and the cost of the material for the sides and top is 20¢/square inch. A.) What is the formula to find the cost of materials for the box? (4 points) B.) Show work using the first or second derivative test to find the dimensions of the box that will minimize the cost C.) What is the minimum cost? (2 points)