Question: What is the primary purpose of the S1 CDMA2000 Tunnelling function in E-UTRAN?
Option 1: To transport CDMA2000 signalling between UE and CDMA2000 RAT for mobility and circuit switched fallback scenarios.
Option 2: To manage LTE-specific signalling for handovers within E-UTRAN networks only.
Option 3: To facilitate data transfer between UEs on different CDMA2000 networks (HRPD and 1xRTT).
Option 4: To handle voice calls exclusively for UEs transitioning from E-UTRAN to CDMA2000 1xRTT.
Explanation: The correct answer accurately reflects the function's role in transporting CDMA2000 signalling for mobility (handovers) from E-UTRAN to CDMA2000 networks and circuit switched fallback to CDMA2000 1xRTT, maintaining service continuity between network types.