Final answer:
HMO is the managed care plan that requires preauthorization for medical services such as surgery.
Step-by-step explanation:
Out of the given options, the managed care plan that typically requires preauthorization for medical services such as surgery is HMO (Health Maintenance Organization).
HMOs have a primary care physician who coordinates the patient's care and refers them to specialists when necessary. Before undergoing surgery or certain medical procedures, the patient usually needs to obtain preauthorization from the HMO to ensure that it is medically necessary and covered by the plan.