Finish the following sentence with the best choice: How to harden leather

Choices:
- Heat the oven to 400 degrees. Then put the shaped leather in the oven for about 10 minutes.
- Cool the leather to 40 degrees. Then put the shaped leather in the refrigerator for about 10 minutes.

Answer:
Heat the oven to 400 degrees. Then put the shaped leather in the oven for about 10 minutes.