Karl Marx spent most of his life researching at the British Museum on the nature of class society and the role of the working class in developing its own ideology of socialism whereby society will no longer be run by the bourgeosie but instead, by the advanced elements of the working class to serve the needs of the vast majority of the people, similar to what the government does in Cuba to provide basic free healthcare, education and such conditions as a lower child mortality rate than the US for example. Karl Marx and his partner in Britain, Friedrich Engels believed that the working class was born out of the socialized production of the Industrial Revolution wherein large numbers of workers were concentrated in single factories or mines. They also believed that the new working class was the most scientific class and the strongest class and most numerous in the history of the world and totally capable of forging a new people oriented  society. Marx died before the Russian Revolution in 1917.
Old Major, the boar in George Orwell's book, the Animal Farm, exhorted the animals to rebel against their human masters who were oppressing them. He died before he could see the success of the animals in this endeavour. 
        
                    
             
        
        
        
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Hello! I would say your answer is C, court opinion.
A court opinion is something used in court - it announces the final decision of the judge, as well as restates a lot of the important parts of the court case. This has to do with the law, so it should be very formal. 
On the other hand, a letter to your grandmother should be casual as it is a personal matter. A newspaper article is going to be as formal, but it is not regarded with as high importance as something on the legal side. An instruction manual will also be formal, but, same reasoning as a newspaper article.
Hope this helps!