For a local product inventory feed, the necessary attribute is the “store code.”

• location ID
• item_code
• product_type
• store code

The correct answer is: store code

Explanation: The “store code” attribute plays a pivotal role in a local product inventory feed. This attribute, represented as [store_code], is case-sensitive and should align with the store codes listed in your Business Profiles. Furthermore, if you are tapping into the merchant-hosted local storefront (full) feature, it’s essential to include the “price” attribute, ensuring it mirrors the price on your landing page.

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