Question: What actions should a UE take upon broadcast MRB release for MBS broadcast service?
Option 1: The UE shall only release the PDCP entity and RLC entity.
Option 2: The UE shall release the PDCP entity, RLC entity, as well as the related MAC and physical layer configuration, and also release the SDAP entity if it has no associated MRB.
Option 3: The UE shall only indicate the release of the user plane resources for the mbs-SessionId to upper layers.
Option 4: The UE shall not take any action upon broadcast MRB release.
Explanation: Upon broadcast MRB release for MBS broadcast service, the UE should release the PDCP entity, RLC entity, as well as the related MAC and physical layer configuration. Additionally, if the SDAP entity associated with the corresponding mbs-SessionId has no associated MRB, the UE should also release the SDAP entity and indicate the release of the user plane resources for the mbs-SessionId to upper layers. This ensures that all relevant resources are released when the broadcast MRB is terminated.