Finish the following sentence with the best choice: How to test if a toilet is running.

Choices:
- Drop some food scraps into the tank. Wait a few minutes. If you see the food scraps flowing into the bowl, take a trip to your local hardware store to pick up a new flapper.
- Drop some food coloring into the tank. Wait a few minutes. If you see the food coloring bleeding into the bowl, take a trip to your local hardware store to pick up a new flapper.

Answer:
Drop some food coloring into the tank. Wait a few minutes. If you see the food coloring bleeding into the bowl, take a trip to your local hardware store to pick up a new flapper.