Answer:
The correct answer would be b. triggered by changes in the weather.
Hibernation is a state of inactivity and lower metabolism generally observed in endotherms.
This state is characterized by slow breathing, slow heart rate, low body temperature, and low metabolic rate.
It helps most of the endotherms to survive through the cold seasons.
For example, beer hibernate in winters.
Thus, weather change can trigger hibernation.
