Question: Upon upper layer request for PDCP entity release for a radio bearer on Uu or PC5 interface, what action does the UE take regarding stored PDCP SDUs in the receiving PDCP entity for UM/AM DRBs and MRBs?
Option 1: Immediately discard all stored PDCP SDUs without delivering them to upper layers.
Option 2: Deliver stored PDCP SDUs to upper layers in descending order of associated COUNT values after header decompression.
Option 3: Hold the delivery of stored PDCP SDUs until a new PDCP entity is established for the radio bearer.
Option 4: Deliver stored PDCP SDUs to upper layers in ascending order of associated COUNT values after performing header decompression, if not decompressed before.
Explanation: This action ensures that data is delivered to upper layers in a logical and sequential manner (based on COUNT values), and any compressed headers are properly decompressed for efficient processing, aligning with the principles of reliable data transfer in telecom networks.