Question: What action does a mobile station take when it is in the MM IDLE state and NORMAL SERVICE, and timer T3212 expires?
Option 1: Perform location updating procedure
Option 2: Perform IMSI detach
Option 3: Respond to paging
Option 4: Perform periodic updating
Explanation: According to the specifications, when a mobile station is in the MM IDLE state and NORMAL SERVICE, it performs periodic updating at the expiration of timer T3212. This ensures that the network remains aware of the mobile station's location and can efficiently manage resources.