A company's revenue from car sales, C (in thousands of dollars), is a function of advertising expenditure, a, in thousands of dollars, so C = f(a). (a) What does the company hope is true about the sign of f'? O The company hopes f'(a) is always positive. O The company hopes f'(a) is always negative. O The company hopes f'(a) equals zero. O The company has no sign preference. O The company hopes f'(a) is sometimes negative and sometimes positive. (b) What does the statement f'(100) = 2 mean in practical terms? O f'(100) means that if the advertising budget is $2,000, the company's revenue is $100. O f'(100) means that if the advertising budget is $100,000 the company's revenue is $2. O f'(100) means that if the advertising budget is $100,000 each extra dollar spent on advertising will bring in about $2 worth of sales. O f'(100) means that the company must sell 2 cars in order to pay for $100,000 worth of advertising. O f'(100) means that if the advertising budget is $2,000, each extra dollar spent on advertising will bring in about $100 worth of sales. How about f'(100) = 0.5? O f'(100) means that if the advertising budget is $5000, each extra dollar spent on advertising will bring in about $100 worth of sales. f'(100) means that if the advertising budget is $100,000, the company's revenue is $0.50. O f'(100) means that if the advertising budget is $5000, the company's revenue is $100. O f'(100) means that the company must sell 100 cars in order to pay for $0.50 worth of advertising. O f'(100) means that if the advertising budget is $100,000, each extra dollar spent on advertising will bring in about $0.50 worth of sales. (c) Suppose the company plans to spend about $100,000 on advertising. If f'(100) = 2, should the company spend more or less than $100,000 on advertising? What if f'(100) = 0.5? O In both cases, the company should spend more on advertising. O In both cases, there is no advantage to changing how much is spent on advertising. O Less should be spent if f'(100) = 2, but more should be spent if f'(100) = 0.5. O More should be spent if f'(100) = 2, but less should be spent if f'(100) = 0.5. O In both cases, the company should spend less on advertising.