Question: What is a requirement for an IoT device that can access a 5G PLMN in direct network connection mode using a 3GPP RAT?
Option 1: The IoT device must have a non-3GPP subscription.
Option 2: The IoT device must be identifiable by the core network, but does not require a 3GPP subscription.
Option 3: The IoT device can operate without any subscription.
Option 4: The IoT device must have a 3GPP subscription.
Explanation: According to the service requirements for the 5G system, an IoT device that can access a 5G PLMN in direct network connection mode using a 3GPP RAT must have a 3GPP subscription. This ensures secure identification and management of the IoT device within the 5G network.