9 Which of the following statements is false? A. Under the high-low method, the costs at the hightest and the lowest levels of activity are always used to analyze a mixed cost. B. A scattergraph plot is used as a first step to diagnose cost behavior before applying the high-low method or the least squares regression method. C. Both the high-low method and the least squares regression method utilize only two data points to produce estimates. D. Both the high-low method and the least squares regression method rely on the assumption that the relation between a mixed cost and the level of activity is linear. E. The least squares regression method is generally more accurate than the high-low method