To guarantee that physical gift cards are always available for purchase, particularly during high-demand periods like the holidays, the best approach is: A. Create an inventory record with an unlimited Allocation value. This setup ensures that the inventory system does not impose a limit on the number of gift cards sold, effectively treating them as always available regardless of actual stock levels. This method is typically used for items that do not physically run out, such as gift cards, where the primary concern is the availability of the codes rather than physical stock.

This practice is supported by the inventory management strategies in Salesforce Commerce Cloud, where setting an inventory to unlimited allocation can be particularly useful for non-tangible items or services. This approach is mentioned in the "Inventory Management" section of the Salesforce Commerce Cloud documentation.