Answer:
According to How the Other Half Lives, the one reason which makes it dangerous to live in buildings in city slums D: Buildings were very dark.
Step-by-step explanation:
Jacob Riis was a police reporter and a social reformer. His book version of “How the other half lives” was published and highlighted the plight of the people living in tenement apartments. Immigrants who had just come to United states for a better life lived in these tenements. The living conditions were pathetic. Buildings were overcrowded, poorly ventilated and quite dark. They did not even have proper sanitation, so pests and bugs were a common problem there. There were children working in factories or were newsboys or garment workers.