Question: What triggers the update of the MS Network Capability field in a telecom network?
Option 1: Periodic polling of User Equipment (UE) by the Serving GPRS Support Node (SGSN)
Option 2: Successful completion of a voice call via Circuit Switched (CS) fallback
Option 3: PDP context activation or GPRS attachment for the served Mobile Station (MS)
Option 4: Handover of a UE from one Base Station Controller (BSC) to another
Explanation: The MS Network Capability field is updated based on network capability information received from the served Mobile Station (MS) during PDP context activation or GPRS attachment, ensuring the network is aware of the MS's capabilities for efficient resource allocation and service provision.