Which of the following is not a common element in many Anti$-$Kickback Statute safe harbors and Stark exceptions?

Group of answer choices

The amount charged or paid must be specified in a value$-$based payment arrangement approved by the Center for Medicare & Medicaid Services $($CMS$).$

The amount charged or paid must be set out in a contract of at least a year$$s duration.

The amount charged or paid must be fair market value.

The amount charged or paid may not vary based on the volume or value of referrals.