A multinational corporation seeks to fortify the security of the top-level user credentials across its numerous cloud accounts, where each account functions under its own operational domain. They intend to put into effect a two-step verification process for all top-level user logins and establish an automatic mechanism for monitoring any top-level credential usage in API calls. Which service should they utilize to automate the monitoring of such activities throughout all operational domains?
AWS Identity and Access Management (IAM)
Amazon CloudTrail
AWS Config
AWS GuardDuty