Question: What happens when a Mobile Station (MS) receives an ACTIVATE PDP CONTEXT REJECT message with a cause code indicating "insufficient resources" and the request type was set to "emergency"?
Option 1: The MS will include a Back-off timer value IE in the next ACTIVATE PDP CONTEXT REQUEST message.
Option 2: The MS will not attempt another PDN connectivity procedure for the same APN in S1 mode.
Option 3: The network shall not include a Back-off timer value IE in the ACTIVATE PDP CONTEXT REJECT message, and the MS may inform the upper layers of the failure to establish the emergency bearer.
Option 4: The MS will immediately attempt another PDN connectivity procedure for the same APN in A/Gb or Iu mode.
Explanation: According to the text, if the SM cause value is #26 "insufficient resources" and the request type was set to "emergency", the network shall not include a Back-off timer value IE. In this case, the MS may inform the upper layers of the failure to establish the emergency bearer, which can result in the upper layers requesting establishment of a CS emergency call or initiating other implementation-specific mechanisms.