The correct answer is C. The customer is using older Gen9 Synergy compute modules, and the required improvement is hardware-rooted platform security. Silicon Root of Trust is an HPE firmware security capability anchored in server hardware and iLO, designed to validate firmware before boot and protect the platform from compromised firmware. HPE states that Gen10 servers introduced Silicon Root of Trust, and Gen11 systems continue that trusted-security model with enhanced iLO capabilities. Option A is incorrect because a firmware update cannot retrofit Silicon Root of Trust into Gen9 hardware that lacks the required silicon foundation. Option B misrepresents HPE OneView Global Dashboard; it provides aggregated management visibility, not centralized distribution of encryption keys and CA-signed certificates to all nodes. Option D can improve administrative integration and role control, but it does not address the deeper platform-trust gap created by the older compute generation. Reference/topics: HPE security architecture, Silicon Root of Trust, iLO security, Synergy Gen9-to-Gen11 modernization, hybrid-infrastructure protection.