When utilizing "Inbound CID Reformatting" rules, what caller ID will an extension display if receiving a call from the number 8135791691?

The answer indicating that the extension will display 5791691 reflects the functionality of "Inbound CID Reformatting" rules within 3CX. These rules are designed to modify the caller ID format to suit the organization’s requirements or to maintain a consistent format across incoming calls.

In this scenario, the inbound caller ID number 8135791691 starts with a prefix, which is likely part of the area code (813 in this case). If the reformatting rules have been configured to remove the area code and just display the local portion of the number, the result would be 5791691. This approach is often used to streamline how caller IDs are presented to end users, enhancing readability and user experience.

The other options reflect potential formats that are not aligned with the typical reformatting logic or fail to remove the appropriate components based on the rules that may be set up in the 3CX system.