Final answer:
The Medicaid expansion under the Affordable Care Act primarily benefits low-income individuals by extending eligibility to millions of the poorest Americans, including adults earning up to 133 percent of the federal poverty level. Therefore, the correct option is c.
Step-by-step explanation:
Supporters of the Medicaid expansion under the Affordable Care Act (ACA), commonly known as Obamacare, argue that the expansion primarily benefits low-income individuals. The expansion was designed to transform Medicaid from just a government health-insurance program for poor families into a broader program, including millions of the poorest Americans. It targeted able-bodied adults under 65 who earn no more than 133 percent of the federal poverty level, significantly increasing access to healthcare for low-income persons not otherwise eligible for Medicaid. While the elderly also receive a large portion of Medicaid spending, they are primarily covered by Medicare, and thus not the focus of this particular expansion.