The civilizations of the Huang River valley and the Nile River valley were similar as both were ruled by dynasties. Option D is correct.
A dynasty is understood as a sequence of rulers from the same family, usually in the context of a feudal or monarchical system, but sometimes also appearing in elective republics. The longest-surviving dynasty in the world is the Imperial House of Japan, otherwise known as the Yamato dynasty, whose reign is traditionally dated to 660 BC.
