Which step is essential for due diligence when buying electronics from an unfamiliar source?

Which step is essential for due diligence when buying electronics from an unfamiliar source?

• A. Checking serial numbers against stolen property databases and obtaining receipts
• B. Verifying ownership but skipping receipts
• C. Obtaining receipts and verifying ownership and serial numbers
• D. Relying on the seller's word

Answer: (C)