Which AWS service assists migration planning by discovering and collecting configuration, usage, and behavior data from on-premises data centers?

AWS Application Discovery Service is the correct answer because it specifically helps enterprises plan migration projects by identifying on-premises applications, their dependencies, and performance characteristics. It collects configuration, usage, and behavior data from servers, databases, and network devices, which is crucial for a successful migration strategy. AWS Resource Groups allow you to organize your AWS resources, but they don't discover on-premises assets. AWS Service Catalog enables organizations to create and manage catalogs of IT services approved for use on AWS, not for on-premises discovery. AWS Systems Manager helps you manage your AWS infrastructure and on-premises resources after they are known, but it doesn't perform the initial discovery of on-premises environments for migration planning.