Which of the following statements related to cost estimation methods is true? O a. 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. o b. The most complex method of cost estimation is the high-low method. cc The least-squares regression method is the most accurate and reliable method to determine the cost behavior compared to scatter-graph plot and high-low methods. d. None of the given answers. e. Only high-low method has a slope and an intercept