Here's a problem to solve: How are warm-blooded animals different from cold-blooded animals?

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

- A: Warm-blooded animals have a higher metabolism in warm weather.
 
- B: Warm-blooded animals are more aggressive in captivity.
 
- C: Warm-blooded animals always have a higher blood temperature.
 
- D: Warm-blooded animals normally maintain a fairly constant internal temperature at all air temperatures.
 