Questions: When you check out at the bookstore, the cashier scans a on the book to identify the product.

The answer is the first one: bar code.

Explanation for each option:

• Bar code: This is the correct answer. A bar code is a series of lines and spaces of varying widths that can be scanned by a machine to identify a product. It is commonly used in retail to track inventory and sales.
• Scan code: This term is not commonly used in the context of identifying products at checkout. It might be confused with the process of scanning, but it is not the correct term for the identifier itself.
• Laser code: This term is incorrect. While a laser is often used to scan a bar code, "laser code" is not a term used to describe the identifier on the product.
• Zip code: This is incorrect. A zip code is a postal code used by the postal service to identify locations for mail delivery, not for identifying products at a bookstore.

Summary: The correct term for the identifier scanned by the cashier to identify the product is "bar code."