Unsettled conditions in the land led to exodus of hundreds of its citizens.

The correct answer is D. expulsion.

Expulsion is the act of forcing someone to leave a place, especially their home country. It can be done for a variety of reasons, such as political or religious persecution, or economic hardship.

Invasion is the act of entering a country or region with an armed force, typically with the intention of conquering or controlling it.

Entry is the act of coming into a place or country.

Immigration is the act of coming to live permanently in a foreign country.

In the context of the question, the unsettled conditions in the land led to the forced removal of hundreds of its citizens. This is an example of expulsion.