Question: What is the primary purpose of the "Common Transport Channel Resources Release" procedure initiated by the Serving RNC (SRNC) in the UTRAN Iur interface?
Option 1: To request release of Common Transport Channel Resources for a given User Equipment (UE) in the Drift RNC (DRNS), potentially releasing both D-RNTI and C-RNTI or just the C-RNTI.
Option 2: To establish a new connection for a UE in the DRNS using the connection-oriented mode of the signalling bearer.
Option 3: To modify existing QoS parameters for a UE's dedicated channel in the DRNS.
Option 4: To request resource allocation for a UE handover from the SRNC to the DRNC.
Explanation: This is correct because the question accurately reflects the described purpose of the "Common Transport Channel Resources Release" procedure as per the given context. It is used by the SRNC to release Common Transport Channel Resources for a UE in the DRNS, which may involve releasing both the Downlink Radio Network Temporary Identifier (D-RNTI) and the Cell Radio Network Temporary Identifier (C-RNTI), or just the C-RNTI. This procedure's focus on resource release, specifically for Common Transport Channels, aligns with Option 1. The other options are incorrect as they describe different procedures or modes not aligned with the context provided.