Question: Under which scenario(s) must a Mobile Station (MS) request suspension of GPRS services from the network due to inability to communicate on GPRS channels?
Option 1: When entering dedicated mode without Class A mode support, during CS connection handover from Iu to A/Gb mode without CS/PS support, and when handed over to a cell not supporting its operational mode (e.g., DTM in a non-DTM cell).
Option 2: Only when the MS enters dedicated mode and Class A operation is not supported.
Option 3: Exclusively during handover from Iu to A/Gb mode if CS/PS mode is unsupported, or when an MS's operational mode (like DTM) is incompatible with the target cell.
Option 4: None of the above scenarios necessitate a request for GPRS service suspension due to communication inability on GPRS channels.
Explanation: This option correctly encompasses all specified scenarios where an MS must request GPRS service suspension due to limitations preventing GPRS channel communication. These include: (1) entering dedicated mode without Class A support, (2) handover from Iu to A/Gb mode without CS/PS capability, and (3) being handed over to a cell incompatible with the MS's operational mode (e.g., a DTM MS in a non-DTM cell). Each of these scenarios necessitates suspension to maintain network and device functionality.