The correct answer is D.
The Communist Manifesto, written by Marx and Engels, mostly supports the so-called social-class struggle. They distinguished two social classes: workers (proletariats) and the owners of the means of production (burgeoisie). They considered that, while the burgeoisie members enriched themselves, they exploited those who worked for them, because proletariats worked in very poor and dangerous conditions and for a low salary, during the first industrialization waves.
Therefore, Marx and Engels encouraged proletariats to fight for their rights (strikes, sit-ints, etc) and to combat their oppresors.
