Which historical event encouraged the migration of  two million iranians to europe, north america, and australia in less than 30 years?

C. the islamic revolution

Islamic revolution.

Explanation:

The Islamic revolution started in the 1979, the country of the Iran and was it opposed the western secular policies of the authoritarian Shah, the Iran Mohammad Reza Pahlavi and opposed the government.  And the campaign of the civil resistance and the western imperialism and overlay the amphibious economic pan of the opposite and corrupt party.

Ithink its deforestation.

The correct answer is a)  a resource with a limited supply; it will run out.