An IAM user is trying to perform an action on an object belonging to some other root account’s
bucket.
Which of the below mentioned options will AWS S3 not verify?

A.
The object owner has provided access to the IAM user

B.
Permission provided by the parent of the IAM user on the bucket

C.
Permission provided by the bucket owner to the IAM user

D.
Permission provided by the parent of the IAM user

Explanation:
If the IAM user is trying to perform some action on the object belonging to another AWS user’s
bucket, S3 will verify whether the owner of the IAM user has given sufficient permission to him. It
also verifies the policy for the bucket as well as the policy defined by the object owner.
http://docs.aws.amazon.com/AmazonS3/latest/dev/access-control-auth-workflow-objectoperation.html