Image: The VergeAT&T can’t pull the plug on landline service for customers across California. In a ruling on Thursday, the California Public Utilities Commission (CPUC) rejected AT&T’s request to release it from its obligations as a Carrier of Last Resort (COLR), as reported earlier by Ars Technica and CBS News.AT&T has had a COLR designation in California since 1996, which ensures everyone in the state has access to affordable and reliable telephone service. Some people in California — especially those who live in remote areas — have come to rely on their landline service, as it allows them to make emergency calls even when the power is out or cellular service isn’t available.Earlier this year, AT&T asked CPUC to be released from its duties as a…