Question: What is the primary purpose of a Closed Subscriber Group ID (CSG ID) in a Public Land Mobile Network (PLMN)?
Option 1: To identify a specific User Equipment (UE) within the PLMN.
Option 2: To authenticate a subscriber's access to a particular cell or group of cells.
Option 3: To uniquely identify a Closed Subscriber Group (CSG) in the PLMN associated with a CSG cell or group of CSG cells.
Option 4: To prioritize traffic for a specific group of subscribers within the PLMN.
Explanation: A CSG ID is used to identify a specific group of subscribers who have access to a particular cell or group of cells, allowing for targeted services and restrictions. This identifier is unique within the scope of the PLMN and is defined in TS 23.003.