Answer:c. the long-run shift or movement in the time series observable over several periods of time.
Step-by-step explanation:
trend
Trend is an observable change that occurs slowly in an output or it can be the observed change in a particular series of points which approaches a particular direction at a certain period and can be seen by a line or curve on the graphs.
For example we can observe a trend in Forex trading graphs to see how a particular currency is doing so that we may determine our next move in trending or in buying stocks or selling stocks.