Sumerian civilization is the oldest known ancient civilization in the world. About this civilization, scientists get information based on of clay tablets with wedge inscriptions, which tell about the way of life, beliefs, religion, trade, etc. This is done thanks to the Sumerian writing system, which is one of the oldest writing systems, called the Sumerian Cuneiform. It is a wedge letter from Mesopotamia, Persia, which is preserved on clay tablets, and which, due to its phonetic characteristic, was easily deciphered. Also, the simplicity of this letter enabled the texts of the ancient civilization to be written down and preserved.
The answer is: A.
