How can this information can be entered and de-duplicated against existing individuals in the Nonprofit Success Pack (NPSP)?

A nonprofit organization uses a vendor for direct mail, and receives a monthly spreadsheet from it with donor information, donation amounts, and the solicitation campaign that the donation was in response to.

How can this information can be entered and de-duplicated against existing individuals in the Nonprofit Success Pack (NPSP)?
A . Use the Salesforce Data Loader to upload the spreadsheet and then manually check for duplicates and use the NPSP Contact Merge tool to de-duplicate records.
B. Upload the spreadsheet using the NPSP Data Importer and associate the individuals with Opportunities and Recurring Donations.
C. Use the Salesforce Import Wizard to upload the spreadsheet and then de-duplicate records using the NPSP Contact Merge tool.
D. Upload the spreadsheet using the NPSP Data Importer and associate the individuals with Opportunities and Campaigns.

Answer: D