Finish the following sentence with the best choice: How to mix a carton of juice before serving it

Choices:
- Take the carton in one or two hands, and keep it closed. Shake it firmly to make the contents mix together.
- Take the carton in one or two hands, and open it. Shake it firmly to make the contents mix together.

Answer:
Take the carton in one or two hands, and keep it closed. Shake it firmly to make the contents mix together.