The required attribute in a local product inventory feed is the “store code.”

• item_code
• location ID
• product_type
• store code

The correct answer is: store code

Explanation: The “store code” attribute is a crucial component in a local product inventory feed. This case-sensitive attribute must align perfectly with the store codes provided in your Business Profiles. For those utilizing the merchant-hosted local storefront (full) feature, there’s another vital aspect to remember: the price attribute in the local products inventory feed. It’s essential that this price mirrors the one showcased on your landing page for consistency.

Read more here: https://support.google.com/merchants/answer/3061342