Karl marx, who wrote the communist manifesto, denounced
a. the labor theory of value
c. utopianism
b. the dictatorship of the proletariat
d. the history of the nature of the state

He denounced utopianism - C

He is most widely known for laying out the idea for a communistic society in the Communist Manifesto where, among other things, he said that the proletariat would govern and have political power in a new type of society. He also laid our the idea of the labor theory of value in one of his other works (Capital). 

Gave a little freedom to blacks