To prevent a third party from identifying a specific user as having previously accessed a service provider through an SSO operation, SAML uses which of the following?

Transient identifiers in SAML are one-time, ephemeral subject identifiers generated fresh for each authentication session and discarded afterward. Because each session produces a different identifier, an external observer or colluding service provider cannot link separate authentications back to the same user, directly fulfilling the unlinkability privacy requirement described in the SAML specification.

SOAP calls are a messaging transport used to carry SAML protocol messages and have no role in anonymizing user identity.

Discovery profiles in SAML assist clients in locating the correct identity provider and are not related to protecting user identity across sessions.

Security bindings define how SAML messages are bound to underlying transport protocols for integrity and confidentiality, not for user identifier obfuscation.