Which technology spread to the Indus River Valley around 5000 BC?

The correct answer pertains to the spread of polished stone technology to the Indus River Valley around 5000 BC. This period marked significant advancements in tool-making and the development of agricultural practices among early societies. Polished stone tools represent a technological leap that allowed for more efficient farming, hunting, and gathering.

The use of polished stone tools enabled people to create sharper, more durable implements, which likely contributed to the enhancement of subsistence strategies within the region. The emergence of these tools indicates a transition toward more sophisticated lifestyles, essential for the future growth of urban centers in the Indus Valley.

In contrast, the other technologies listed either emerged later or were not as pivotal during the timeframe specified. Iron tools, for instance, became prominent much later, while advanced irrigation systems developed concurrently with urbanization but were not the primary focus in the early phases of the Indus Valley's agricultural practices. Similarly, while ceramic artifacts are significant and were certainly present in the region, polished stone technology is more specifically tied to the era around 5000 BC and its relevant impact on early Indus Valley societies.