Which of the following are NOT valid member types for a queue?

Queues in Salesforce are used for organizing and distributing work among users. They can have various types of members that can be assigned to take on tasks or cases from the queue.

When considering valid member types for a queue, it's essential to note that profiles are fundamentally linked to user permissions and access levels within the Salesforce platform, rather than being a direct member of a queue. User groups, roles, and public or private groups can be assigned to queues in order to ensure the right users are able to access and work on records from that queue, whereas profiles do not serve this purpose.

Private groups, public groups, and roles and subordinates all represent the correct types of members that can inherently be part of a queue in Salesforce, thereby facilitating collaborative work and task management. Therefore, profiles do not function in this capacity, making them an invalid member type for queues.