Respuesta :
Choice (c) is the correct answer. Working conditions became insufferable during the industrialization period, with long hours, dangerous conditions, and few (if any) tangible benefits being the norm. This is what led to books like "The Jungle" and the stories of muckraking journalists, as a way of exposing this level of corruption and danger.
You are correct, out of the choices given, the best answer is definitely more dangerous working conditions. Because of industrialization and the presence of more machines, work hours became longer and equipment handling became more hazardous to the workers of companies.