What are two possible origins for trick-or-treating?

Celts believed that as one year passed to the next the dead and living would overlap. They dressed up as demons so if they happened to run into a real demon, the demon would think the person was a demon.

A few centuries later, the Catholics wanted to change the demon dressing holiday a bit, so they created “All Saints Day” where everybody dressed up as angels and saints.

The correct answer is b