Here's a problem to solve: Some frog species will bury themselves in mud if the environment becomes very dry. The frogs enter into a type of hibernation. Which would be the most likely signal for the frogs to emerge from the mud?

Among the 4 following options, which is the correct answer?

- A: a decrease in daylight hours
 
- B: an increase in air temperature
 
- C: an increase in precipitation
 
- D: a decrease in air pressure
 