The correct answer is C and D. To minimize performance and storage issues, a data architect should recommend leveraging on premise data archival and building integration to view archived data, and leveraging big object to archive case data and lightning components to show archived data. These solutions will allow some user groups to access historical cases for up to 7 years without consuming too much storage space or affecting the performance of queries and reports. Option A is incorrect because exporting data out of salesforce and storing it in flat files on external system will make it difficult to access and query the data. Option B is incorrect because creating a custom object to store case history and run reports on it will still consume a lot of storage space and impact the performance of queries and reports.

The correct answer is A. To migrate the data to Salesforce, the data architect should create custom objects to store agent relationships. This will allow the data architect to replicate the look-up table structure from the legacy CRM system and maintain the relationship data in Salesforce. Option B is incorrect because migrating to Salesforce without a record owner will cause errors and prevent the data from being imported. Option C is incorrect because assigning record owner based on relationship will not preserve the agent relationships from the legacy CRM system. Option D is incorrect because migrating the data and assigning to a non-person system user will not allow the users to access and modify the data.

The Individual object is a standard object that lets you store details about data privacy and protection preferences for person accounts, contacts, users, and leads. The Individual object can be used to implement a standard communication preference management model for NTO, with relationships to the other objects.