With Respect to Analyzing the Productivity and Profitability of Sales

With respect to analyzing the productivity and profitability of sales force efforts, all of the statements below are true, except:

A) marketing costs are really a subcategory of selling costs
B) It usually takes a long time to complete a comprehensive assessment of the sales department's effectiveness and efficiency.
C) Because total sales provide an incomplete picture of a firm's sales patterns, sales managers also should evaluate costs and profitability at the same time to reveal strengths and weaknesses of the company's different marketing units.
D) To determine the profitability of different market segments, it's necessary first to analyze the sources of sales volume and then to subtract the costs for producing those sales.