In AWS Identity and Access Management, roles can be used by an external user authenticated by an external identity provider (IdP) service that is compatible with _____.

A. BNML (Business Narrative Markup Language)
B. CFML (ColdFusion Markup Language)
C. SAML 2.0 (Security Assertion Markup Language 2.0)
D. BPML (Business Process Modeling Language)