Which of the following can be used to disallow a system/user from accessing all applications...

The Path rule is used to specify a path to a folder or application and control access based on that path. By setting a Path rule, an administrator can disallow a system or user from accessing all applications except for those located in a specified folder. This is particularly useful for creating a secure environment where users can only run applications from a trusted location, thereby preventing the execution of unauthorized or potentially harmful programs.

References: This explanation is consistent with the principles of application whitelisting and access control in network security, as outlined in the Certified Network Defender (CND) course materials and objectives, which emphasize the importance of controlling access to system resources to protect against threats.