7. At the BPH pharmacy, the demand (number of tablets) for a particular drug has been declining over the years as new treatments have emerged. Demand is higher in winter and spring, as shown in the following table. The pharmacist wants to make sure that he does not order more tablets than needed.

a. Deseasonalize the data.

b. Develop the regression equation for the deseasonalized data.

c. Formulate the trend forecasts for each season of 2017.

d. Adjust the trend forecasts for seasonality and round your estimates to the nearest hundred.