Who propounded the theory of scientific socialism?

Correct option is B

The theory of scientific socialism is most closely associated with Karl Marx, along with Friedrich Engels. Marx's contribution to political philosophy and economics laid the foundation for modern socialism and communism. Scientific socialism refers to the methodology used by Marx and Engels that sought to establish a theoretical framework for socialism based on an analysis of historical and economic laws. Unlike utopian socialism, which was based on idealistic and often impractical visions of society, scientific socialism claimed to be grounded in the objective study of the capitalist system.