Answer: AssumeRole

The correct answer is D. The AssumeRole operation from AWS Security Token Service (STS) allows a developer to use multi-factor authentication (MFA) to access an Amazon S3 bucket in another AWS account. When calling AssumeRole, you can include MFA information to ensure that the user has been authenticated with an AWS MFA device. This is useful in cross-account scenarios where the role's trust policy includes a condition that requires MFA authentication. If valid MFA information is not provided, the request to assume the role will be denied.

Author: LeetQuiz Editorial Team