I believe it would be c. Reasoning Stained glass windows were once used to educate people who could not read. By looking at the painted scenes in the glass, people could learn about the stories of the Bible and religious teachings.
Why were stained glass windows added to cathedrals?
It represents purity, the heavens, spirituality, and genesis. Naturally, windows were an important part of the church, so it's not such a surprise that builders began playing with ways to enhance them. Stained glass provides a certain level of privacy that ordinary windows do not without blocking light transmission.
