Answer : 3. "City-planning system"
Explanation :

This civilization was spread in the Indus River Valley, hence it was named Indus Valley Civilization. Due to the rise of cities for the first time, it is also called the first urbanization. Because of the use of bronze for the first time, it is also called Bronze Civilization. 1400 centers of Indus Valley Civilization have been discovered, out of which 925 centers are in India.