The obelisk is a stone pillar of a four-legged cross section, usually tall, set as a monument or ornament. The top of the obelisk is in the shape of a pyramid, and since it is made of full stone, there is no interior, where artifacts could be placed. They are set up at the entrance to the temples, on graves. They come from the ancient world, they can be found in Egypt, but they also have their Greek version. According to mythology, obelisk related to the ancient Sun God Ra, represented as the primordial mound on which God was standing when he created the world.
The answer is: c.