Which of the following is not an authorization decision identified in the RMF? Response:

Authorization to operate is a core authorization decision in the RMF, granting approval for a system to operate in a specific environment.

Denial of authorization to operate is a core authorization decision in the RMF, signifying that a system does not meet security requirements for operation.

Common control authorization is a core authorization decision in the RMF, allowing specific controls to be inherited by multiple systems.

All of the listed options (Authorization to operate, Denial of authorization to operate, Common control authorization) are indeed identified as authorization decisions within the RMF. The RMF process concludes with a formal decision to authorize a system's operation, deny it, or authorize common controls by the authorizing official.