Can variant inventory quantity be returned in a product's storefront JSON endpoint?

The correct answer indicates that variant inventory quantity can indeed be returned in a product's storefront JSON endpoint. This is significant because the storefront JSON API is designed to provide essential product details to improve user experience on e-commerce sites.

When requesting information about products, it is crucial for merchants and developers to have access to accurate inventory data at the variant level. This allows merchants to display available stock directly on product pages, helping customers to make informed purchasing decisions. The inclusion of inventory data at this level ensures that customers know if a product variant is in stock or unavailable at the moment of browsing, which can enhance the shopping experience and reduce the chances of cart abandonment.

The other options suggest limitations or conditions that do not apply; the inventory quantity is consistently available across all themes and product types, as it is a core feature of the Shopify platform aimed at providing customers and developers with comprehensive product information.