A Bucket Owner Has Allowed Another Account's IAM Users to Upload

Multiple Choice

A bucket owner has allowed another account's IAM users to upload or access objects in his bucket. The IAM user of Account A is trying to access an object created by the IAM user of account B. What will happen in this scenario?

A) It is not possible to give permission to multiple IAM users
B) AWS S3 will verify proper rights given by the owner of Account A, the bucket owner as well as by the IAM user B to the object
C) The bucket policy may not be created as S3 will give error due to conflict of Access Rights
D) It is not possible that the IAM user of one account accesses objects of the other IAM user