Finish the following sentence with the best choice: How do I solidify the chocolate balls ?

Choices:
- Set the covered ball on a tray covered by sheet of aluminium foil and put the tray in the freezer for one hour.
- Set the covered ball on a tray covered by sheet of aluminium foil and put the tray in the microwave for one hour

Answer:
Set the covered ball on a tray covered by sheet of aluminium foil and put the tray in the freezer for one hour.