Before the russian revolution what form of government was the head of russia?

Russia had an autocratic government prior to the Russian Revolution, being ruled by one person, Tsar Nicholas II. It did have an elected body called the Duma, which was instituted after a small revolution in 1905 by Tsar Nicholas II, however it had virtually no power to make laws that the Tsar had to honor. It was more like an advisory body, so it cannot be said that it had a true democracy prior to the revolutions of 1917.

The answer would be a