Time-series data may exhibit which of the following behaviors?

A) trend
B) random variations
C) seasonality
D) cycles
E) They may exhibit all of the above.

Time-series data can exhibit trend (a consistent upward or downward movement over time), random variations (unpredictable fluctuations), seasonality (repeating patterns based on seasonal factors such as weather or holidays), and cycles (long-term repeating patterns such as economic booms and busts). Therefore, it is possible for time-series data to exhibit all of the above behaviors.