The ratio MB A :MB B :MB C is 5:2:1 at any thickness. For example, at a thickness of 0 feet, MB A = $1,000, MB B = $400, MB C = $200, and at a thickness of 5 feet, MB A = $500, MB B = $200, MB C = $100. The marginal cost (MC) of building an additional foot of thickness is $800. Draw the diagram, label the curves (lines), and show numbers.