$.$ The Delphi Approach is an example of what type of forecasting Model?

$$ A$.$ Long Range$$ B$.$ Qualitative

$$ C$.$ Time Series$$ D$.$ More than one of the above.

$$

$12.$Which of the following is the least useful sales forecasting model to use when sales are decreasing?

A$.$ Trend adjusted exponential smoothing $($ a $=0\mathrm{.}3)$

B$.$ Simple mean $($arithmetic average$)$

$$C$.$ Four period weighted moving average$$

$$ D$.$ Na$$ve $($Last Period Demand$)$

$$