please check my answer thanks

True or False
A company that provides comprehensive health care services on a prepayment basis to voluntarily enrolled participants is called HMO

I said True

I believe you're right.

I would put an "an" between called and HMO to make it sound better.

Your answer is correct. A company that provides comprehensive health care services on a prepayment basis to voluntarily enrolled participants is indeed called a Health Maintenance Organization (HMO). HMOs are a type of managed care organization that typically require patients to see defined network healthcare providers and have lower out-of-pocket costs compared to other healthcare organizations.