Question: Which of the following is NOT considered as part of the delay-critical PDCP data volume for MAC delay status reporting in a transmitting PDCP entity?
Option 1: Delay-critical PDCP SDUs without constructed PDCP Data PDUs
Option 2: PDCP Control PDUs not yet submitted to lower layers
Option 3: Successfully transmitted PDCP Data PDUs for AM DRBs (already acknowledged by the receiver)
Option 4: All PDCP SDUs pending transmission, regardless of their delay criticality
Explanation: For MAC delay status reporting, the transmitting PDCP entity considers specific types of data as part of the delay-critical PDCP data volume, emphasizing 'delay-critical' PDCP SDUs. Option 4 is incorrect because it includes all pending PDCP SDUs, regardless of their delay criticality, which contradicts the specification's focus on 'delay-critical' SDUs.