$$Waiting$-$line models often are used in capacity planning in order to

A$.$

evaluate different capacity expansion alternatives when demand is uncertain.

B$.$

select an appropriate capacity cushion for a high$$ customer$-$contact process.

C$.$

understand why forecast accuracy declines as the forecasting horizon lengthens.

D$.$

analyze the payoff of a series of$$ events, such as$$ competitors' actions, which requires a sequence of decisions regarding capacities.