Climatex Inc., which manufactures air conditioning units for commercial buildings to order, has seen significant fluctuations in its delivery costs from month to month, as the following data indicates for part of the month. year 2020. Number of units delivered Total delivery costs June 4 2 200$ July 7 3 100$ August 5 2 600$ September 2 1 500$ October 3 2 200$ November 6 3 000$ December 8 3 600$ a) Calculate the variable cost of delivery charges per unit using the end point method.