You use CloudFormation templates to deploy web applications on EC2 instances. During initialization, the applications download Bash scripts from an S3 bucket to install the necessary dependencies. The S3 bucket has enabled versioning. One day, the web applications failed to launch because a script in the S3 bucket has been mistakenly deleted by a new hire. The script is very old and no one has a backup. How would you quickly restore the script in the S3 bucket?

Answer options:

A.In the Amazon S3 console, select the deleted object, download the previous version of the object and upload the downloaded file to the S3 bucket with another name. Modify the CloudFormation templates to use the new file.
B.Modify the CloudFormation templates to use the previous version of the deleted object by adding the previous version ID.C.In the Amazon S3 console, choose the “List versions” switch, select the deleted script and undelete it by deleting the delete marker.
D.Deleted objects cannot be recovered or restored in an S3 bucket that has enabled versioning.

Correct Answer: C
Option A is incorrect because with this method, you have to change all CloudFormation templates. You can simply undelete the S3 object by removing the delete marker.
Option B is incorrect because similar as
Option A, CloudFormation templates have to be modified. You should restore the S3 object by deleting the delete marker.
Option C is CORRECT because by deleting the delete marker, the object is restored and EC2 instances can fetch the object successfully. The following is an example of deleting the delete marker:
Option D is incorrect because if the S3 bucket has enabled versioning, all versions of objects remain in the bucket even if you delete them.
Reference:
https://docs.aws.amazon.com/AmazonS3/latest/user-guide/undelete-objects.html