Which solution will meet these requirements MOST securely?
Configure each AWS account to use a single email address that the company manages. Ensure that all account owners can access the email account to receive notifications. Configure alternate contacts for each AWS account with corresponding distribution lists for the billing team, the security team, and the operations team for each business unit.
Configure each AWS account to use a different email distribution list for each business unit that the company manages. Configure each distribution list with administrator email addresses that can respond to alerts. Configure alternate contacts for each AWS account with corresponding distribution lists for the billing team, the security team, and the operations team for each business unit.
Configure each AWS account root user email address to be the individual company managed email address of one person from each business unit. Configure alternate contacts for each AWS account with corresponding distribution lists for the billing team, the security team, and the operations team for each business unit.
Configure each AWS account root user to use email aliases that go to a centralized mailbox. Configure alternate contacts for each account by using a single business managed email distribution list each for the billing team, the security team, and the operations team.
Explanations:
Using a single email address that all account owners can access may not be the most secure solution, as it relies on shared access to one email account, which could lead to security risks.
Although using distribution lists for different business units is a good practice, assigning administrator email addresses to the lists for responding to alerts is not the most secure or efficient way to handle notifications.
Configuring the root user email address to a single individual for each business unit is not ideal, as the root user email should not be used for such purposes. Root user accounts should be limited and monitored to prevent misuse.
Using email aliases that go to a centralized mailbox for the root user, combined with configuring alternate contacts for each category (billing, security, operations), ensures security and proper management of notifications without relying on individual root email accounts.
I plot that the answer is:
Configure each AWS account root user to use email aliases that go to a centralized mailbox. Configure alternate contacts for each account by using a single business managed email distribution list each for the billing team, the security team, and the operations team.