The correct answer is D. Maintenance procedures should be considered when examining fire suppression systems as part of a data center environmental controls review. Fire suppression systems are critical for protecting the data center equipment and personnel from fire hazards. Therefore, they should be regularly maintained and tested to ensure their proper functioning and compliance with safety standards. Maintenance procedures should include inspection, cleaning, replacement, and repair of the fire suppression system components, as well as documentation of the maintenance activities and results. Installation manuals, onsite replacement availability, and insurance coverage are notdirectly related to the fire suppression system performance and effectiveness, and therefore are not relevant for the audit review. References: CISA Review Manual (Digital Version)1, page 403.