A user authenticates through an IdP.

Answer A is correct. Zscaler recommends SCIM provisioning over JIT-only provisioning because SCIM can proactively synchronize users and groups at scheduled or on-demand intervals, rather than waiting for a new login assertion. Those synchronized groups can receive ZIA and ZPA service entitlements and can be referenced as SCIM group criteria in Private Access policies. ZPA can also evaluate SAML session attributes when those attributes are required, but administrators should define one authoritative mapping and investigate any discrepancy between the SAML assertion and the SCIM directory state. Entity ID selects or identifies the IdP; it does not itself create the correct authorization group. NameID, MFA status, and firewall rules likewise do not replace service entitlement and group assignment. See Zscaler’s external IdP guidance and SCIM identity-management configuration.