Here's a problem to solve: Under which circumstance would an adaptation be useful that allows tadpoles to go through a shortened period of metamorphosis?

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

- A: when tadpoles need to swim immediately
 
- B: when there is a limited amount of water in their environment
 
- C: when there is a decrease in the number of predators
 
- D: when tadpoles need to blend in with their surroundings
 