It’s all of the above. We can see columns and we can also see symmetry which is when things are symmetrical obviously so the answer is d
True it is used for a foreground
The color gold was common in Byzantine paintings.
The walls are where you would need to chose the colors carefully because if, for example, your trying to get a gloomy mood you would want grey walls. But if you want/need a room with a happy mood you would maybe want pink or yellow or green light airy colors like a nice blue as well. Other than the walls i would say that you would have to carefully choose the colors would maybe be the ceiling because when you look up you could see the colors that were chosen to make a nice or whatever else feeling.