The correct answer is A. On Cisco MDS 9000 Series switches, the command device-alias confirm-commit enables a confirmation step when committing the pending device-alias database. Cisco documentation states that when this command is enabled, issuing device-alias commit causes the switch to display the pending differences on the console and then prompt the user for confirmation (Yes or No) before the changes are actually committed. This matches both requirements in the question exactly: the engineer is prompted before commit, and the pending changes are explicitly shown.
Option C is incorrect because device-alias commit performs the commit action itself, but by itself it does not guarantee that the pending diff will be displayed and confirmed first. That behavior is specifically controlled by device-alias confirm-commit. Option B is incorrect because enhanced device-alias mode relates to how aliases are managed and distributed in the fabric, not to prompting or displaying pending differences during commit. Option D affects distribution behavior and optimization, not console confirmation. Therefore, the only command that satisfies the stated operational and visibility requirements is device-alias confirm-commit