The best option to complete the diagram shown is A- the Russian revolution.
The Russian Revolution occurred as a result of several factors including the Loss to Japan in the Russo-Japan war and losses in WWI.
There was also the fact the the leadership did not care about the needs and agitations of the people, and the anger the landless peasants felt.
In conclusion, option A is correct.
Find out more on the Russian Revolution at https://brainly.com/question/810738.
