A company is storing 700 terabytes of data on a large network-attached storage (NAS) system...

This answer is correct because it meets the requirements of moving the data efficiently and without disruption, and still being able to access and update the data during the transfer window. AWS DataSync is an online data movement and discovery service that simplifies and accelerates data migrations to AWS and helps you move data quickly and securely between on-premises storage, edge locations, other clouds, and AWS Storage. You can create an AWS DataSync agent in the corporate data center to connect your NAS system to AWS over the Direct Connect connection. You can create a data transfer task to specify the source location, destination location, and options for transferring the data. You can start the transfer to an Amazon S3 bucketand monitor the progress of the task. DataSync automatically encrypts data in transit and verifies data integrity during transfer. DataSync also supports incremental transfers, which means that only files that have changed since the last transfer are copied. This way, you can ensure that your data is synchronized between your NAS system and S3 bucket, and you can access and update the data during the transfer window.