Final answer:
Government spending on older adults mainly rises due to increased healthcare costs, amplified by the aging Baby Boomer population requiring more elder care and assisted living services.
Step-by-step explanation:
According to Burtless, the primary reason government spending on older adults continues to climb is c) Rising Healthcare Costs. This take into consideration the increasing percentage of the aging population due to the retirement of Baby Boomers.
As the senior population grows, there's a significant change in social institutions, including a massive shift in the need for elder care and assisted living facilities, as well as an increase in healthcare demand which results in elevated Medicare budgets.