Answer:
Because they used tactics of non-violence
Hope this helped
Options A, and D are the right answers, that he established Duma, and freed the slaves.
In his October manifesto of 1905, Tsar Nicholas II ( the emperor of Russia who ruled between 1894 and 1917), established the Duma (a representative assembly). And in 1861, he introduced significant agrarian reforms and hence, he declared all the serfs to be freed.
Other options do not come under his reforms as russification was the name of the policy of the Alexander III, and Peter the great the first emperor of Russia who established the constitutional monarchy.
If we’re talking Stalin, it’ll be gulags.