Which of the following statements related to cost estimation methods is true? O a. None of the given answers. b. The most complex method of cost estimation is the high-low method. Oc. The high-low method is the most accurate and reliable method to determine the cost behavior compared to scatter-graph plot and least-squares regression methods. O d. The three methods determine a slope and an intercept. O e. The scatter-graph method is used to derive an estimated line of cost behavior by graphically connecting the two cost amounts identified with the highest and lowest volume levels