Question: Who initiates the Radio Access Bearer (RAB) establishment, modification, and release functions in a UTRAN network?
Option 1: User Equipment (UE)
Option 2: Universal Terrestrial Radio Access Network (UTRAN)
Option 3: Core Network (CN)
Option 4: Both UTRAN and CN jointly
Explanation: The Core Network (CN) controls the establishment, modification, or release of a RAB towards the UTRAN. This is based on factors like subscription, service, requested QoS, etc., highlighting the CN's role in managing bearer resources and services for a UE across the network.