Question: In the context of Generic Bootstrapping Architecture (GBA) as per 3GPP standards, what is the primary purpose of the `Nhss_GbaSDM_Unsubscribe` service operation initiated by an NF (Network Function) consumer?
Option 1: To request periodic updates for newly subscribed GBA Subscriber data types.
Option 2: To unsubscribe from receiving updates for previously requested GBA Subscriber data types.
Option 3: To modify the key associated with a specific GBA Subscriber data type.
Option 4: To query the current status of all available GBA Subscriber data types.
Explanation: The correct answer is Option 2 because the `Nhss_GbaSDM_Unsubscribe` service operation is specifically designed for the NF consumer to stop receiving updates for GBA Subscriber data types that were previously requested. This operation aligns with managing subscriptions, ensuring the consumer only receives necessary updates, thus optimizing network resource utilization and respecting data privacy.