Read this excerpt from Friedrich Engels’s The Condition of the Working Class in England. Every great city has one or more slums, where the working-class is crowded together. . . . The streets are generally unpaved, rough, dirty, filled with vegetable and animal refuse [trash], without sewers or gutters, but supplied with foul, stagnant pools instead.

Which point does Engels make in this passage?

Industrialization has created poor living conditions.
Mass production has led to the birth of industrial cities.
Steam-power machinery has destroyed the environment.
Workers in cities need to try harder to improve their living conditions.