Which one of the following statements about the patterns of a demand series is false?

Select one:

A$.$ The trend, over an extended period of time, always increases the average level of the series.

B$.$ The five basic patterns of most business demand series are the horizontal, trend, seasonal, cyclical, and random patterns.

C$.$ Every demand series has at least a random component.

D$.$ Estimating cyclical movement is difficult. Forecasters do not know the duration of the cycle because they cannot predict the events that cause it$.$