Which AWS service will meet these requirements?

Explanations:

AWS DataSync is used for automating data transfer between on-premises storage and AWS, but it does not provide file system protocols for applications.

AWS Snowball Edge is a data transfer service that physically transports data to AWS. It does not support direct integration with applications using file system protocols.

Amazon S3 File Gateway allows on-premises applications to access Amazon S3 through standard file protocols (like NFS and SMB), making it ideal for the stated requirements.

AWS Transfer Family is primarily for transferring files over SFTP, FTPS, and FTP into and out of S3, but does not support traditional file system protocols for applications.