Who is most likely to experience the greatest amount of caregiver burden?

I believe the answer is: Ida, who is single and cares for her 85-year-old mother who is suffering from dementia and does not want any help

For most caregiver, the economic and physical burden that hey made for someone they care for would be diminished by emotional reward that they get from the caregiving.
When caring dementia patient, the caretakers often wouldn't receive any of this emotional reward.

Dcalifornia they have the most people with 200+ people per square mile