The implementation of which features of an identity management system reduces costs and administration overhead while improving audit and accountability?

Two-factor authentication improves security and authentication assurance but actually increases administration overhead by managing additional authentication tokens or devices, and does not primarily target cost reduction or audit accountability.

Single Sign-On reduces the number of credentials users must manage and can improve user experience, but it primarily addresses authentication convenience rather than directly reducing administration overhead or improving audit and accountability across identity management.

User self-service reduces IT administration costs by delegating routine identity tasks (password resets, account unlocks, profile updates) directly to end users, eliminating helpdesk tickets and associated labor costs. Self-service portals generate detailed audit logs of user-initiated actions, improving accountability and traceability. This combination of cost reduction, reduced administrative burden, and enhanced audit capability makes it the correct answer.

A metadirectory synchronizes identity data across multiple directory services and improves data consistency, but it is primarily an infrastructure integration tool and does not directly address cost reduction, administration overhead, or audit accountability in the way self-service does.