Answer the following question with respect to the excel file test10-data posted above in canvas. assume that the forecast for period 6 is not produced using exponential smoothing but is known to be 90. for periods 7-11, exponential smoothing with an alpha = 0.4 is used to produce the forecast. which of the following statements is true? group of answer choices a. the period 11 forecast is 90 b. the period 9 forecast is 82.29 c. the alpha has to be changed to get a better forecast d. the period 9 forecast is 92.48