Answer:
The answer is A- Bolster their expertise in trading.
Step-by-step explanation:
The Sumerians were the first Mesopotamin civilization, They lived in independent walled city-states, 90% of the population were involved in farming as their economy was based on agriculture, which was influenced by major technological advances in Mesopotamin history. They traded by land with the Mediterranean and by seas as far as India. They are also well known for their metalwork. They transformed how humans cultivated food, built dwellings, communicated and kept track of information and time.
They mad ingenious use of materials such as clay which was then the plastic of the ancient world as they had few trees,almost no stone or metal. They made everything from bricks to pottery to tablets for writing. They also had the ability to take inventions that had been developed elsewhere and apply them on a much bigger scale. This way they could mass-produce goods such as textiles and pottery that they could then trade with other people.
The Sumerians wrote multiplication tables on clay tablets and dealt with geometrical exercises and division problems. The Sumerians developed a formal numbering system based on units of 60. At first, they used reeds to keep track of the units, but eventually, with the development of cuneiform, they used vertical marks on the clay tablets. Their system helped lay the groundwork for the mathematical calculations of civilizations that followed.