Question: When a Mobile Equipment (ME) responds with "ME currently unable to process command", which of the following additional information values indicates the ME is occupied with a specific type of transaction, as per 3GPP standards for USIM Application Toolkit?
Option 1: '01' = ME currently performing a voice call
Option 2: '03' = ME currently busy on SS (Supplementary Service) transaction
Option 3: '05' = ME undergoing a software update
Option 4: '10' = ME experiencing battery low condition
Explanation: According to the specified standards for USIM Application Toolkit, when an ME is unable to process a command and is busy with an SS (Supplementary Service) transaction, it must provide additional information with the value '03'. This specific value ('03') is designated to inform about the ME's current engagement in an SS transaction, thereby aiding in diagnostics and appropriate action by the requesting entity.