Cisco UCS Manager, a core component of the FlexPod architecture, supports several user authentication methods. Local authentication utilizes the built-in user database on the Fabric Interconnects, essential for initial setup and emergency access. For integration with enterprise identity sources, UCS Manager uses remote authentication protocols. LDAP is a standard protocol supported for querying external directory services. Active Directory is a specific and common directory service that UCS Manager integrates with by configuring an LDAP provider. While Active Directory uses the LDAP protocol, it is treated as a primary, supported authentication source. UCS Manager also supports RADIUS and TACACS+, which were not provided as options.

A. NetBIOS: This is a network protocol for name resolution and session services, not a centralized user authentication method supported by Cisco UCS Manager.

E. Workgroup: This describes a peer-to-peer networking model and is not a mechanism for centralized user authentication in an enterprise system like UCS Manager.

1. Cisco UCS Manager Administration Guide, Release 2.2, User Management Chapter: This guide explicitly details the supported authentication methods. It states, "Cisco UCS Manager supports the following types of user authentication: Local, LDAP, RADIUS, TACACS+." It further clarifies the relationship between Active Directory and LDAP in the section "Authenticating Users with Active Directory," explaining, "You can configure Cisco UCS to have Cisco UCS Manager authenticate users with Microsoft Active Directory. To do this, you must configure an LDAP provider for the Active Directory server..." This supports that Local, LDAP, and Active Directory (via LDAP) are the intended correct methods from the options.

2. Cisco UCS Manager GUI Administration Guide, Release 4.1, Chapter: User Management, Section: Authentication: "Cisco UCS Manager supports the following authentication methods: Local, LDAP, RADIUS, and TACACS+." This document confirms that Local and LDAP are primary, officially documented authentication realms.

3. FlexPod Datacenter with Cisco UCS M5, NetApp AFF A-Series, and VMware vSphere 7.0 Design Guide (NVA-1142-DESIGN), Page 51, Section: Create Authentication, Roles, and Privileges: This official NetApp and Cisco Validated Design guide outlines the configuration steps for UCS Manager within a FlexPod solution, which include creating local users and configuring remote authentication domains using protocols like LDAP to connect to services such as Active Directory.