Final answer:
The Zhou dynasty was the first in China to use iron, marking the transition from the Bronze Age to the Iron Age in China.
Step-by-step explanation:
The first dynasty in China to use iron was the Zhou dynasty. The Zhou dynasty (1046-256 BCE) not only coexisted with the Shang dynasty towards the end of their reign but eventually overthrew them. The Zhou dynasty witnessed significant advances in agriculture that spurred population growth, and importantly, with the discovery of iron in the mountains, they began to develop methods of extracting and melting iron, thus heralding the iron age in China, a full millennium before Europe adopted similar techniques.