Answer:
Correct order:
The Indus civilization declined.
Eurasian migrants crossed into India.
Scholars wrote the Vedas.
Step-by-step explanation:
The first civilization of India emerged in the river valley of Indus in the 3rd Millennium BC, with the developed cities such as Mohenjo Daro and Harappa that disappeared during the migrations of Indo-Aryans that came here in the 2nd Millennium BC. Those migration established new ruling class in this area. Aryans who came here wrote Vedas, who are both religious and historical source for this period.