I'm guessing you're writing an SAQ. I can't write it for you, but here are some ideas.
A) You can write about how industrialization had led to mass immigration to cities to fill factory positions, which directly led to the creation of a large working class population and the development of the wealthy middle class. You can also talk about how Karl Marx called these classes the proletariat and the bourgeoisie.
B) You can perhaps say that lack of union representation made it very difficult for workers to voice their issues and concerns on multiple topics like low wages and working conditions. This made it difficult to get their voices heard, so they were not able to get the resources or pay they needed to move about society.
C) Communism/Marxism is the easiest one to go with. It should be very easy to talk about how Marx saw the industrial revolution as reinforcing the idea of class struggles throughout history and how he believed the bourgeoisie were oppressing the working-class proletariat with the only solution being a violent revolution and "dictatorship of the proletariat". Mention the Communist Manifesto.
