The correct answer is D) fingers, hair, and clothing often got caught in the gears and belts of machines.
The sentence that provides key details is "fingers, hair, and clothing often got caught in the gears and belts of machines."
We are referring to the factory work an the dangers and risks it represented for workers. The sentence is very detail in that explicitly says the parts of the body or clothing that got caught in the gears and belts of machines. Working conditions in factories were not good at all at the time. Indeed, people worked in unhealthy conditions, long hours and no ventilation.
