A “central log-in” means users can authenticate using a centralized account database rather than separate local accounts on each PC—this is a core feature of a Windows domain . Mike Meyers explains that a Windows domain makes it easy for anyone with a domain account to log on to any computer in the domain with a single account , a process called “single sign-on (SSO),” and that users do not need a separate local account stored on every computer. The All-in-One guide reinforces the same: in a domain, the domain controller stores domain accounts and “a user logging on to any computer on the domain may use their one domain account to log on to the entire network.”

Active Directory is the directory service commonly used to implement domains, but the question asks what is required for centralized logon on the workstation side— the computer must be joined to the domain (domain membership). Workgroups use only local accounts, and Local Group Policy Editor manages policies locally, not centralized authentication.