PLEASE HELP ASAP

Which of the following best explains why animals that inhabit warmer regions tend to have smaller body sizes?

A higher surface-area-to-volume ratio facilitates heat loss.
Animals in warmer climates need to move more quickly to catch prey.
More species inhabit warm climates, and smaller size enables a greater number to live in the same ecosystem.
Smaller body size enables faster reproduction and repopulation to maintain a niche in overpopulated warmer climates.