NTO has outgrown its current salesforce org and will be migrating to new org shortly.

The correct answer is A, B, and D. To maintain the relationship hierarchy during migration, a data architect should use data loader to export the data from source org and then import or upsert into the target org in sequential order, create an external ID field for each object in the target org and map source record IDs to this field, and replace source record IDs with new record IDs from the target org in the import file. These steps will ensure that the records are linked correctly and the relationships are preserved. Option C is incorrect because redefining the master detail relationship fields to lookup relationship fields in the target org will change the behavior and security of the data model. Option E is incorrect because keeping the relationship fields populated with the source record IDs in the import file will cause errors and prevent the records from being imported.