What permission should be enabled for external users to see all other users in the organization?

The correct permission that should be enabled for external users to see all other users in the organization is the "Enable View All Users" permission. This permission specifically allows users to view user records within the organization, making it possible for external users to have visibility over all users, regardless of their role or profile settings. This is crucial in scenarios where you want external collaborators or users to interact with and engage with various members of the organization.

The other permissions listed serve different purposes. "Enable View Profiles" relates to the ability to view user profiles but does not provide the same level of visibility over all users. "Enable Access All Records" is broader and pertains to access permissions for all records, not specifically for user visibility. "Enable Manage External Users" focuses on the ability to manage external users rather than granting visibility to all users in the organization. Thus, enabling "View All Users" directly addresses the requirement of ensuring external users can see the entire user list.