Objective: What is the best way to check if a baby's milk isn't too hot?

Which of the following solutions is more sound in terms of naive physics reasoning?

OPTIONS:
- Sprinkle a few drops on the inside of your baby's wrist to check the temperature.
- Sprinkle a few drops on the inside of your wrist to check the temperature.
Sprinkle a few drops on the inside of your wrist to check the temperature.