A Significant Weakness of the High-Low Method Is That

A significant weakness of the high-low method is that

A) a significant amount of management expertise is necessary to break out the variable and fixed costs.
B) the two data points that are used may not be representative of the general relationship between cost and activity.
C) the calculations are so complex that a computer is usually necessary in order to get accurate results.
D) monthly data must be collected for at least three years before the method can be used.