Question: In which mode does a Mobile Station (MS) perform periodic routing area updates?
Option 1: PMM-CONNECTED mode
Option 2: PMM-IDLE mode and PMM-CONNECTED mode
Option 3: PMM-IDLE mode
Option 4: Neither PMM-IDLE nor PMM-CONNECTED mode
Explanation: The Mobile Station (MS) performs periodic routing area updates in PMM-IDLE mode, as it is required to update its location with the network periodically when not actively connected. In contrast, PMM-CONNECTED mode does not require periodic routing area updates since the MS is already connected and its location is known to the network.