Answer: b.Religion simply kept the Proletariat in their low social class.
Explanation: Karl Marx was a German political philosopher, economist, historian, sociologist, journalist and revolutionary socialist. Marx's critical theories about society, economics and politics were about class struggle. In capitalism, this manifests in the conflict between the ruling classes (known as the bourgeoisie) that control the means of production and the working classes (known as the proletariat) that enable these means by selling their labour power in return for wages.
The second one, the word "after" requires a comma sometime after it.
