How can these requirements be met?

Universal containers is importing 1000 records into Salesforce. They want to avoid any duplicate records from being created during the import.

How can these requirements be met?
A . Include a column in the import file that has either record names, Salesforce IDs, or external IDs that can be used to match records.
B . When importing the file, select the “Prevent Duplicates” option on the last step of the Import Wizard and import the file.
C . After importing all of the custom objects, run a duplicate check report, export the record to a CSV File, and run a mass delete to purge any duplicates.
D . After importing all of the custom objects, review all records created and manually merge or delete and duplicate record

Answer: A