Finish the following sentence with the best choice: How to paint the box for a solar air heater?

Choices:
- Paint the box either black or any dark shade so that the heat is absorbed and trapped within the box for efficient heating.
- Paint the box in silver color on both the exterior and interior so that their is a feedback cycle of heating happening within the box.

Answer:
Paint the box either black or any dark shade so that the heat is absorbed and trapped within the box for efficient heating.