Ayyatolah Khomeini became the supreme leader of the Islamic Rebublic of Iran in 1979, after years of fighting in the alliance with the West, to overthrow last Shah of Iran Mohammad Reza Pahlavi. Thus, the millennium monarchy in Iran was overthrown and the theocratic Islamic Republic of Iran was established. After the Revolution Ayyatolah Khomeini became the supreme leader of Iran, a position created by the constitution of the Islamic Republic as the highest religious and political priority of the nation.
The answer is: D.