Question: In a V2X (Vehicle-to-Everything) communication scenario, when a service consumer updates an "Individual PC5 Provisioning Requirement Subscription" using an HTTP PUT request, which of the following attributes **MUST REMAIN UNCHANGED** from their previous values?
Option 1: `notifUri` (Notification URI), `plmnList` (PLMN ID List)
Option 2: `ueId` (Remote V2X UE ID), `serviceId` (V2X Service ID), `appQosReq` (Application QoS Requirements)
Option 3: `ueId` (Remote V2X UE ID), `serviceId` (V2X Service ID)
Option 4: `groupId` (V2X Group ID), `plmnList` (PLMN ID List)
Explanation: According to the specified procedure for updating an "Individual PC5 Provisioning Requirement Subscription" via HTTP PUT, the attributes that must remain unchanged from their previous values are the `ueId` (Remote V2X UE ID) and the `serviceId` (V2X Service ID). This ensures consistency in the provisioning requirement subscription, maintaining the integrity of the service's configuration.