Final answer:
The correct answer is China. It was not situated by a river and its mountainous terrains isolated its cities, unlike the river-centric civilizations of Mesopotamia, Egypt, and the Indus Valley.
Step-by-step explanation:
The ancient society in question, which was not situated by a river and had mountainous terrains that effectively isolated cities from one another, is China. Unlike Mesopotamia, Egypt, and the Indus Valley where early civilizations were centered around major rivers like the Tigris, Euphrates, and the Nile, which provided fertile land and resources vital for the development of cities, ancient China's geography included mountainous terrains which made inter-city communication and travel more challenging.
This contributed to the unique development of Chinese civilization, with a degree of isolation leading to distinct cultural and political development relative to civilizations in Mesopotamia and Egypt.