Answer:
Option C.
Step-by-step explanation:
Iron, is the right answer.
The period the Zhou dynasty in the history of China marked the technological advancement and urbanization. This was due to the invention of iron technology during the rule of Zhou dynasty. During this time, the Chinese people used the Iron for making agricultural instruments and weaponry. The use of iron tools in agriculture improved the production of goods and sustained a large population and also advanced technologies of war.