The Harappan Civilisation declined as a result of (a) Aryan invasion (b) Decline in foreign trade (c) Ecological factors (d) Not definitely known factors
option d. Though the purpose of the decline isn't always known, however thru excavations it's far clean that fall of the Harappan Civilization took place among 1800 BC to 1700 BC. It is usually believed that the Aryans had been the following settlers.
