Final answer:
Iron technology provided certain groups with significant advantages in terms of weaponry and toolmaking over those using bronze or copper technologies, leading to increased productivity and military capability.
Step-by-step explanation:
The technology that gave certain groups an advantage over others was b) Iron technology. Iron is more abundant than copper, the main component of bronze, and although harder to extract and work with, it represents a significant advancement once the smelting techniques were developed. With iron, more people could own metal tools and weapons because it was both cheaper and tougher than bronze. This facilitated greater productivity of land and labor, allowing fewer people to grow more food, cut down trees more efficiently, among other activities. Furthermore, iron's superiority in strength compared to bronze revolutionized warfare, allowing for more effective weapons and armor.