Question: What is the specific Domain Name used in the host part of a SIP URI to indicate confidentiality protection of Mission Critical (MC) Services identities?
Option 1: mc1-encrypted.3gppnetwork.org
Option 2: mc-secure.identity.org
Option 3: protected.mc-services.3gpp.net
Option 4: encrypted-mc.3gppnetwork.com
Explanation: The correct Domain Name, as per the specified telecom standard for indicating confidentiality protection of MC Services identities in a SIP URI's host part, is indeed 'mc1-encrypted.3gppnetwork.org'. This specific string signals that the user part of the SIP URI contains a protected MC Services identity, ensuring confidentiality across Mission Critical Communications (MCC) services like MCPTT, MCData, and MCVideo.