Your client is working with an agency to set up a product feed in Google Merchant Center, but the agency is not sure which attributes to include. Which attribute is optional?

In the Google Merchant Center product feed, the product_type attribute is considered optional, whereas attributes like price, image_link, and availability are strictly required for the feed to be processed and for items to be eligible for Shopping ads. While not mandatory for account approval, providing a product_type is highly recommended because it allows advertisers to use their own internal classification system to organize and partition products into specific product groups within a campaign. By including this data point, you gain more granular control over bidding and reporting, even though Google does not require it to identify the basic commercial characteristics of the item.