Question: What type of attach procedure is not applicable for NB-S1 mode, according to the EPS protocol?
Option 1: EPS attach for normal service
Option 2: EPS emergency bearer services and EPS RLOS attach
Option 3: EPS attach for SMS only
Option 4: Both EPS emergency bearer services and EPS RLOS attach
Explanation: According to the EPS protocol, both EPS emergency bearer services and EPS RLOS attach procedures are not applicable for NB-S1 mode. This is because these procedures require specific network capabilities that may not be supported in NB-S1 mode. Therefore, UEs operating in NB-S1 mode cannot initiate these types of attach procedures.