The AMR field in Salesforce Login History is meaningful only when the upstream identity provider includes authentication-method information in a way Salesforce can understand. Salesforce can surface AMR information from modern federation patterns, but the actual authentication methods must be asserted by the IdP. That is why architects need to think about protocol support and IdP implementation. The field is useful because it shows how the user authenticated upstream, for example whether MFA or another method was used. High-assurance session settings are related to policy enforcement, but they do not by themselves populate AMR. The key design point is that AMR is an observation of the IdP's authentication methods, not an independent Salesforce-generated fact. This is why options A, C work together as the correct solution.