In fiscal year 2020, Walmart Inc. (WMT) reported annual revenue of $559.15 billion, gross profit of $138.84 billion, and net income of $13.51 billion. Costco Wholesale Corporation (COST) had revenue of $166.8 billion, gross profit of $21.82 billion, and net income of $4.06 billion. a. Compare the gross margins for Walmart and Costco. b. Compare the net profit margins for Walmart and Costco. c. Which firm was more profitable in 2020 ? a. Compare the gross margins for Walmart and Costco. The gross margin for Walmart is %. (Round to two decimal places.) The gross margin for Costco is %. (Round to two decimal places.) b. Compare the net profit margins for Walmart and Costco. The net profit margin for Walmart is %. (Round to two decimal places.) The net profit margin for Costco is %. (Round to two decimal places.) c. Which firm was more profitable in 2020? (Select from the drop-down menu.) was more profitable in 2020