Question: What is the correct format for deriving a default W-APN Operator Identifier from an IMSI, specifically for the Mobile Network Code (MNC) with only 2 significant digits?
Option 1: w-apn.mnc12.mcc<MCC>.pub.3gppnetwork.org
Option 2: w-apn.mnc012.mcc<MCC>.pub.3gppnetwork.org
Option 3: w-apn.mnc120.mcc<MCC>.pub.3gppnetwork.org
Option 4: w-apn.mnc0012.mcc<MCC>.pub.3gppnetwork.org
Explanation: According to the 3GPP specification for deriving a default W-APN Operator Identifier from an IMSI, if there are only 2 significant digits in the MNC, one "0" digit shall be inserted at the left side to fill the 3 digits coding of MNC. Therefore, for an MNC with only 2 significant digits (e.g., "12"), the correct format would pad it with a leading zero, resulting in "mnc012". This ensures consistency in the DNS translation format (`w-apn.mnc<MNC>.mcc<MCC>.pub.3gppnetwork.org`).