Question: What is the condition under which a UE may deactivate the AS layer and activate Power Saving Mode (PSM) when timer T3324 expires?
Option 1: The UE is attached for emergency bearer services or has a PDN connection for emergency bearer services.
Option 2: The UE is in EMM-IDLE mode, has no PDN connection for emergency bearer services, and is not attached for access to RLOS.
Option 3: The UE receives an "Extended wait time" from lower layers and timer T3324 has expired, but only if the UE had already been allocated timer T3324 with a value different from "deactivated".
Option 4: The UE is in EMM-REGISTERED.NORMAL-SERVICE state.
Explanation: According to the text, when timer T3324 expires, a UE may deactivate the AS layer and activate PSM if it is in EMM-IDLE mode, has no PDN connection for emergency bearer services, and is not attached for access to RLOS.