Large scale departure of people

A. Migration

B. Emigration

C. Immigration

D. Exodus

Answer: Option D

Solution(By Examveda Team)

One word substitute is Exodus.

Migration: seasonal movement of animals from one region to another.
Emigration: the act of leaving one's own country to settle permanently in another; moving abroad.
Immigration: the action of coming to live permanently in a foreign country.
Exodus: a mass departure of people.