Secure Firewall Management Center must trust the certificate presented by the Cisco ISE pxGrid server. Therefore, the certificate authority certificate that signed the pxGrid node's server certificate must be exported from ISE and imported into Management Center as a trusted CA object. If primary and secondary pxGrid nodes are deployed, Cisco requires their certificates to be signed by the same trusted certificate authority. Depending on the integration design, the engineer might also need the monitoring-node CA certificate and a pxGrid client certificate with its private key for Management Center. However, the question specifically asks which certificate establishes trust with the pxGrid server node. SAML and domain-controller certificates are unrelated, and a certificate cannot simultaneously be self-signed and signed by a third-party CA. Cisco ISE and Secure Firewall certificate integration