In the assignment dataset with more recent electricity bill data (2022-2024), both the high-low method and regression analysis were less efficient predictors of the total cost equation than the same two methods were with the example data (2019-2021). Choose the response that it the most logical explanation for why the predictive value has declined. Question 4Select one: a. Changes in the method in which Delivery Charges, a category of costs on the bill but which have no cost detail, are calculated and charged. b. Changes in the monthly base charge and the energy charge (i.e., the cost per kilowatt hour). c. The variance in the number of days included in the monthly billing cycles. d. Changes in the rate of sales tax