Aging in the past was very different than how it is nowadays, political inventions like retirement plans are relatively new. In the early 20th century it was a well known social norm for young adults to be in charge of the well being of their older parents, it was considered to be a way of being thankful to the parents. During that century the living conditions were extremely hard and even for young people the mortality rate was huge. So it was safer for the aging parents to just stay home and work in simpler tasks while younger adults would work and support them economically.
So definetly, the correct answer answer is D