Final answer:
Seasonal variability of precipitation is the best predictor of fires among the options given, as it influences drought conditions and vegetation dryness, both of which contribute to fire risk.
Step-by-step explanation:
The best predictor of fires among the options provided is c) Seasonal variability of precipitation. The reason for this is that changes in precipitation patterns can lead to either drought conditions or periods of heavy moisture. Drought can make forests and grasslands particularly susceptible to fires, as dry vegetation burns more easily. Additionally, the timing of precipitation is crucial; for instance, significant rainfall in the early growing season followed by a dry spell can lead to increased vegetation growth and then create abundant dry fuel for fires later on. Annual temperature also plays a role as higher temperatures can contribute to drier conditions and therefore increase fire risk. It's important to note that climate change has been leading to more extreme weather events, altering precipitation and temperature patterns, which can in turn affect fire regimes.