A car dealership keeps track of how much it spends on advertising each month and of its monthly revenue. From this information, the list of advertising expenditures and probable associated revenues are shown in the table below. Advertising (thousands of dollars) Revenue (thousands of dollars) 5 150 7 200 9 250 11 325 13 400 15 450 17 500 19 525 a. Find a cubic polynomial that models the data. b. Find the first derivative and explain what it means in terms of the data. C. d. e. f. Find the relative extremes of the revenue function and explain what they mean in terms of the problem. Find the second derivative and explain what it means in terms of the data. Find the point of diminishing returns and explain what it means in terms of the problem. Graph the function from part a, and label the relative extremes and the point of diminishing returns.