Which of the following statements regarding risk is MOST true? A. It is impossible to have a situation where the market risk of a single stock is less than that of a portfolio that includes the stock. B. The higher the correlation between the stocks in a portfolio, the lower the risk in the portfolio. C. The market portfolio has no unsystematic risk. D. An investor can eliminate virtually all market risk if he or she holds a very large and well-diversified portfolio of stocks