The correct answer is B) It led to trade with other nations.
The ability to work with metal changed Mesopotamian civilization? in that it led to trade with other nations.
When people in Sumeria developed the ability to work and transform metal, they could produce different tools and weapons that gave them a great advantage in trade. They could trade with other civilizations reaching the Aegean Sea and the Indus Valley.
Let's remember that the Sumerians also developed great Agriculture techniques and they knew how to grow good crops in the fertile soil of the land located between the Euphrates and Tigris Rivers.