When new RAID controllers are installed and disks go missing, the first logical step is toreboot to the RAID controller BIOS and rescan for attached disks and arrays (Answer A). This will allow the RAID controller to detect the connected drives and rebuild the RAID configuration as expected. * Rebooting to RAID controller BIOS (Answer A):This step ensures that all the attached disks and arrays are properly detected and mapped to the RAID configuration. * Checking UEFI settings (Option B):This might be useful later, but initially, the RAID controller BIOS should be checked first to verify disk detection. * Turning off external arrays (Option C):While this could be helpful in some scenarios, it's not the most efficient first step. * Checking cables (Option D):This could be necessary, but since the controllers were just replaced, software/BIOS configurations should be checked first. CompTIA Server+ Reference:This topic relates toSK0-005 Objective 3.1: Install and configure server components.