Final answer:
An HMO (Health Maintenance Organization) is a prepaid group health plan where members pay in advance for services and providers receive a fixed amount per enrollee.
Step-by-step explanation:
The organization type that corresponds to prepaid group health plans where members pay in advance for the services of participating physicians and hospitals that have made agreements is A) HMO (Health Maintenance Organization). An HMO provides health care and is paid a fixed amount per person enrolled in the plan, regardless of how many services are provided. This is in contrast to fee-for-service systems, PPOs (Preferred Provider Organizations), POS (Point of Service) plans, and Indemnity Plans, which typically operate on different payment models and do not involve paying in advance for a predefined set of services.