Question: What type of request should a UE include in the ATTACH REQUEST message when initiating an EPS attach procedure to transfer a non-emergency PDU session from N1 mode to S1 mode?
Option 1: handover of emergency bearer services
Option 2: handover
Option 3: existing PDU session
Option 4: existing emergency PDU session
Explanation: According to the text, when a UE intends to transfer a non-emergency PDU session from N1 mode to S1 mode, it should initiate an EPS attach procedure and include a PDN CONNECTIVITY REQUEST message with a request type set to 'handover'. This is specified in the paragraph as '- if the PDU session which the UE intends to transfer is a non-emergency PDU session, the request type is set to 'handover';