Which of the following is not a common element in many Anti$-$Kickback Statute safe harbors and Stark exceptions? The amount charged or paid must be fair market value. The amount charged or paid must be set out in a contract of at least a year's duration. The amount charged or paid may not vary based on the volume or value of referrals. The amount charged or paid must be specified in a value$-$based payment arrangement approved by the Center for Medicare & Medicaid Services $($CMS$).$