Comprehensive and Detailed Explanation From AWS Cloud Documentation:

Only the AWS account root user can create or delete access keys that belong to that root user. AWS documentation for creating root-user access keys requires signing in with root-user credentials and explicitly states that the procedure cannot be performed as an IAM user or IAM role. Therefore, option A is correct when “AWS account owner” is understood as the person signing in as the AWS account root user. Administrator permissions attached to an IAM user, an IAM group, or an administrator group do not convert that IAM identity into the root user and do not authorize it to manage root-user access keys. Root-user access keys are long-term credentials with unrestricted account power, including access to AWS resources and billing information. AWS strongly recommends not creating them. For programmatic access, the safer practice is to use temporary credentials through IAM roles, IAM Identity Center, or another appropriately scoped identity. Root credentials should be protected with multi-factor authentication and used only for tasks that specifically require them. Thus, none of the IAM-user options is valid.