Context: Billy mixes oil and vinegar to make salad dressing. He notices that after a few minutes, the oil and vinegar separate. He wonders what factors affect how quickly liquids separate. So, he decides to design an experiment. He has the following supplies available:
three glass bottles
olive oil
vegetable oil
vinegar
cold water
Using only these supplies, which question can Billy investigate with an experiment?
A. Does vegetable oil separate faster when stirred together with vinegar or with water?
B. Does vinegar separate faster when stirred together with olive oil or with coconut oil?
C. Does vegetable oil separate faster when stirred together with cold water or with hot water?
From the given choices, choose the correct answer and respond with the letter of that choice.

A