Which Medicare plan typically limits enrollees to a network of providers?

Medicare Health Maintenance Organizations (HMOs) are designed to provide care through a specific network of doctors, hospitals, and other providers. Enrollees are typically required to choose a primary care physician within this network and need referrals to see specialists. This structure encourages coordinated care and usually results in lower costs for consumers, but it limits the flexibility in choosing healthcare providers compared to other Medicare plans.

In contrast, Medicare Preferred Provider Organizations (PPOs) also have a network but typically offer more flexibility, allowing enrollees to see out-of-network providers, albeit at a higher cost. Medicare Indemnity Plans and Original Medicare do not restrict beneficiaries to a network, giving them the freedom to see any provider that accepts Medicare. Thus, the defining characteristic of HMOs is the limitation to a network of providers, making this choice the correct answer.