In Magento Open Source, when would a Zero Subtotal checkout be used?

[Reference: Zero Subtotal Checkout | Adobe Commerce - Experience League: https://experienceleague.adobe.com/docs/commerce-admin/stores-sales/payments/offline/zero-subtotal-checkout.html?lang=en, Explanation:, Zero subtotal checkout is a payment method in Magento Open Source that allows customers to complete an order with a subtotal of zero. This can be used in situations where a coupon code covers the full value of the products and shipping., For example, a customer might use a coupon code that provides a 100% discount on all products. If the customer's cart has a subtotal of $100, the coupon code will reduce the subtotal to $0. The customer will then be able to complete the checkout without making any payment., Zero subtotal checkout can also be used in situations where the customer is purchasing downloadable or virtual products. These products have a price of zero, so they can be purchased using zero subtotal checkout., The other options are not correct. Option A is incorrect because zero shipping charges do not apply to zero subtotal checkout. Option B is incorrect because a discount that covers the entire value of the purchase except the shipping charge would still result in a subtotal greater than zero., Therefore, the correct answer is C., , , ]