Finish the following sentence with the best choice: To harden the chocolate on the rainbow cookies after frosting

Choices:
- put the frosted rainbow cookies back in the fridge  and leave them there for an hour or two, until the chocolate hardens
- put the frosted rainbow cookies back in the oven  and leave them there for an hour or two, until the chocolate hardens

Answer:
put the frosted rainbow cookies back in the fridge  and leave them there for an hour or two, until the chocolate hardens