a) why is it that a forecast adjusted for seasonality can never give a
forecast that is worse than the forecast that adjusts for trend but
not for seasonality?

b)think of an actual company where the trend forecast for any quarter
would give a forecast that is close to the forecast adjusted by the
seasonal indices.

c) think of an actual company where the trend forecast for any quarter
would give a forecast that would be vastly higher than the forecast
adjusted for the seasonal indices.