Which one of the following statements is​ correct? A. The​ S&P 500 Index is carefully constructed to reflect the values of​ large, medium and small capitalization companies. B. The​ S&P 500 Index is based on 500 large companies that trade on U.S. exchanges. C. The​ S&P 500 is based on the 500 largest U.S. companies as measured by market value. D. Because of mergers and​ bankruptcies, the​ S&P 500 Index no longer contains 500 stocks.