According to an article in the Wall Street Journal, UPS, the package delivery firm, announced that because of the surge in online shopping during the Covid-19 pandemic, it would charge new fees on packages shipped during the holiday season: "UPS...said the fees could total as much as $3 a package for ground shipments and other lower-priced shipping options and up to $4 a package for air shipments bound for residences." Source: Paul Ziobro, "UPS Plans Hefty Holiday Fees Amid Coronavirus-Related Shipment Surge," Wall Street Journal, August 7, 2020. Suppose that you own a firm that will be shipping packages during the holiday season. Are these UPS fees a fixed cost or a variable cost to you? A. Fixed cost, since the cost of shipping these packages are fixed at $3 for ground shipments and $4 for air shipments. B. Fixed cost, since shipping costs do not change based on how much is being shipped. C. Variable cost, since the cost of shipping these packages depend on whether the package is shipped on the ground or in the air. D. Variable cost, since shipping costs change based on how much is being shipped