Stock Exchanges. What are stock exchanges? How do they facilitate the trading of stocks? Stock exchanges are facilities that: (Select the best answer below.) O A. are used to buy and sell commodities. B. allow investors to purchase or sell existing mutual funds. O c. allow investors to purchase or sell existing stocks OD are used to buy and sell farm animals. Stock exchanges facilitate: (Select the best answer below.) O A. the trading of stocks in the primary market by providing a physical location for trading B. purchases of futures by having investment banks available to provide financing O c. the trading of stocks in the secondary market by providing a physical location for trading D. commodity purchases by having one location for bankers and borrowers