Correct Option: A

Karl Heinrich Marx was a German philosopher, economist, sociologist, historian, journalist, and revolutionary socialist. His ideas played a significant role in the development of social science and the socialist movement. Revolutionary socialist governments espousing Marxist concepts took power in a variety of countries in the 20th century, leading
to the formation of such socialist states as the Soviet Union in 1922 and the People’s Republic of China in 1949. Many labor unions and workers’ parties worldwide were also influenced by Marxist ideas, while various theoretical variants, such as Leninism, Stalinism, Trotskyism, and Maoism, were developed from them.