What Is the Difference Between the Yield-To-Maturity and the Realized

What is the difference between the Yield-to-Maturity and the Realized Compound Yield?

A) They are actually the same concept.
B) The yield to maturity is the actual return,calculated at the end of the investment; the realized compound yield is the expected return at the beginning of the investment.
C) The realized compound yield is the actual return,calculated at the end of the investment; the yield to maturity is the expected return at the beginning of the investment.
D) The yield to maturity continues as far as the first call,the realized compound yield continues until final payment is made.