Question: In the EFSMSS (SMS status) file, what does the coding `b1=0` for the 'SMS Memory Capacity Exceeded' Notification Flag indicate about the UE's memory capacity?
Option 1: The UE has sufficient memory capacity to receive new SMS messages.
Option 2: The UE's memory capacity is exceeded, and it cannot receive new SMS messages until space is freed.
Option 3: The UE is experiencing a temporary issue with message processing, pending a network response.
Option 4: The flag's status is unknown or not set.
Explanation: According to the specification, for the 'SMS Memory Capacity Exceeded' Notification Flag, `b1=0` means the flag is set, indicating that the UE's memory capacity is exceeded. This notification mechanism allows the UE to inform the network when it cannot receive new SMS messages due to lack of memory space, facilitating flow control and ensuring the network can appropriately manage message delivery.