The correct answer is D) they worked hard and had poor diets, so were vulnerable to disease.
Peasants working on medieval manors died young because they worked hard and had poor diets, so were vulnerable to disease.
During Medieval times, life for peasants was hard. They spent most of their lives working all day long. Women and children also helped the father growing crops or feeding and cleaning the animals. They were very poor and the quality of their food was not the best. They lacked nutrients. Another big reason for their vulnerability was that they did not have enough rest hours. Rest is so important for the body to recover after a long day of work. Food and rest are keywords for a good life.
The other options of the question were A) they could be hurt while away from the manor of the Lord's services. B) they receive no or inadequate medical treatment for their illnesses. C) they could be at risk of injury and death during attacked by rival lords.