You decide to create a bucket on AWS S3 called `mybucket` and then perform the following actions in the order that they are listed here.

Answer options:

A.There will be 1 version ID for file1, 2 version IDs for file2, and 1 version ID for file3.
B.The version ID for file1 will be null. There will be 2 version IDs for file2, and 1 version ID for file3.
C.There will be 1 version ID for file1, the version ID for file2 will be null, and there will be 1 version ID for file3.
D.All file version ID`s will be null because versioning must be enabled before uploading objects to `mybucket`.

Answer – B
Objects stored in your bucket before you set the versioning state have a version ID of null. When you enable versioning, existing objects in your bucket do not change. What changes is how Amazon S3 handles the objects in future requests.
Option A is incorrect because the version ID for file1 would be null.
Option B is CORRECT because the file1 was put in the bucket before the versioning was enabled. Hence, it will have a null version ID. The file2 will have two version IDs, and file3 will have a single version ID.Option C is incorrect because file2 cannot have a null version ID as the versioning was enabled before putting it in the bucket.
Option D is incorrect because once the versioning is enabled, all the files put after that will not have a null version ID. But file1 was put before versioning was enabled. So it will have null as its version ID.For more information on S3 versioning, please visit the below link.
http://docs.aws.amazon.com/AmazonS3/latest/dev/Versioning.html