The correct answers are C. External objects and D. Big objects.

External objects are suitable because they represent data stored outside Salesforce while still being accessible in Salesforce. Salesforce documentation explains that external objects behave similarly to custom objects, but the record data is stored outside the Salesforce org. External objects can also participate in lookup-style relationships, including external and indirect lookup relationships, and Salesforce Connect supports reports that include external objects.

Big objects are also suitable for archiving very large volumes of historical data on the Salesforce platform. Salesforce describes big objects as a way to store and manage massive amounts of data, including archived data from other objects. Big objects support querying through SOQL/API patterns, and Salesforce documentation also covers viewing big object data in reports and dashboards, commonly by using a working dataset for reportable subsets.

A is incorrect because “related objects” does not reduce Salesforce data storage.

B is incorrect because moving data into custom objects still consumes Salesforce data storage, so it does not solve the storage-limit issue.

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