Who said “The introduction of foreigners does not necessarily
destroy the nation, they merge in it”?

The correct option is M. K. Gandhi.

Context and Origin of the Quote:
This statement is a notable quote by Mohandas Karamchand Gandhi (M. K. Gandhi) from his seminal work Hind Swaraj (Indian Home Rule), written in 1909. The book is structured as a dialogue between an "Editor" (representing Gandhi's voice) and a "Reader," addressing key concepts of Indian civilization, nationalism, and self-rule.

Explanation of Gandhi's Argument:
In Chapter X of Hind Swaraj, titled "The Condition of India (Continued): The Hindus and the Mahomedans," Gandhi refutes the British colonial premise that India could not be a unified nation due to its vast religious and cultural diversity. He argues that India has always had a rich heritage of assimilation, stating that:
1. A country is a nation when it possesses a natural capacity to absorb and assimilate different cultures and peoples.
2. The arrival of new groups (referred to in the text as "foreigners") does not destroy the pre-existing national identity. Instead, these groups merge into the societal framework, becoming an integral part of the nation's composite culture.
3. True national unity in India does not require everyone to follow the same religion or origin, but rather to coexist harmoniously under a shared civilizational ethos.