ServiceNow supports multiple authentication methods to verify user identities before granting access to an instance. The three valid authentication methods from the given options are:

Local Database Authentication

This is the default authentication method used in ServiceNow.

User credentials (username and password) are stored in the ServiceNow database.

Authentication is handled directly by ServiceNow without relying on external identity providers.

This is useful for small implementations or instances where external authentication is not required.

LDAP (Lightweight Directory Access Protocol)

LDAP allows ServiceNow to integrate withcorporate directory services, such as Microsoft Active Directory, to authenticate users.

Users authenticate using theircorporate credentials, reducing the need to maintain separate user accounts in ServiceNow.

ServiceNow connects to an LDAP server and verifies credentials without storing passwords in the ServiceNow database.

SSO (Single Sign-On)

Single Sign-On enables users to log into ServiceNow using an external identity provider (IdP).

ServiceNow supports various SSO protocols, including:

SAML 2.0 (Security Assertion Markup Language)

OAuth 2.0

OpenID Connect

Kerberos

This allows users to authenticate once and gain access to multiple applications, improving security and user experience.

A. XML feed–

XML feeds are used for data exchange,not authentication.

ServiceNow can consume XML feeds for integrations but does not use XML feeds to authenticate users.

E. FTP authentication–

FTP (File Transfer Protocol) is used for transferring files between systems and isnot a valid authentication methodin ServiceNow.

ServiceNow Docs: User Authentication Methodshttps://docs.servicenow.com/en-US/bundle/utah-platform-administration/page/administer/security/concept/user-authentication-methods.html

ServiceNow CSA Official Training Guide (User Authentication & Security)

Why the Other Options Are Incorrect?References from Certified System Administrator (CSA) Documentation:These references confirm thatLocal Database, LDAP, and SSOare valid authentication methods in ServiceNow.