Which of the following statements is CORRECT?

a. The realized rate of return is denoted simply as a lower-case r. It represents a statistical calculation of what will happen with the stock's future return.

b. The required rate of return is denoted simply as a lower-case r with a straight line on top. This rate of return doesn't represent speculation about a stock's future return but represents the actual return you receive from the stock.

c. The required return represents the return an investor requires to invest in the stock; the expected return is based on a statistical calculation of what will happen with the future value of the stock; and the realized rate of return is the actual, historic return earned on the stock.

d. The actual values of the expected rate of return, the required rate of return, and the realized rate of return must be identical for financial markets to operate.

e. None of the statements above are correct.