When installing an option, a PAC is needed under which condition?

The correct answer pertains to the condition where the option installation status is blank. In this context, a PAC (Program Authorization Code) is required to proceed with the installation of an option because a blank status typically indicates that the system does not recognize the option's authorization. This highlights the need for a PAC to validate and confirm that the installation is legitimate and permissible within the current configuration of the system.

When an option has a blank installation status, it suggests that the system cannot verify whether the necessary permissions or prerequisites for the installation of the option are satisfied. Hence, providing the PAC ensures that the option can be properly authorized and configured in accordance with the system's capabilities and licensing agreements. This process is crucial for maintaining system integrity and ensuring that any added functionalities align with the intended operational parameters of the FANUC system.

In relation to the other conditions mentioned, having a PAC that is incompatible with the version indicates an issue with version compatibility rather than a need for a PAC. A system reboot may be a necessary step after installation but does not directly relate to the necessity of a PAC for initial installation. Lastly, the absence of a connection cable is a hardware issue that would prevent installation from occurring altogether, rather than affecting the need for a PAC.