Which of the Following Statements BEST Describes Accountable Care Organizations

Which of the following statements BEST describes Accountable Care Organizations (ACO) ?

A) ACOs are based on a Medicare waiver program that coordinated cardiac care
B) ACOs are effective coordinating care but ineffective decreasing costs
C) ACOs require risk sharing that is easily tolerated by provider organizations
D) ACOs that left the program did so for operational reasons
E) ACOs are developing at a rapid pace with CMS anticipating all payment models will be transitioned to negative and positive risk sharing models by 2017