R Class Is

R class is:

A) an accrual class of a CMO that makes a payment to bondholders only when preceding CMO classes have been retired
B) the residual class of a CMO, giving the owner the right to any remaining collateral in the trust after all other bond classes have been retired plus any reinvestment income earned by the trust
C) a bond that has some prepayment protection and expected durations of five to seven years depending on the level of interest rates
D) a bond that has the shortest average life with a minimum of prepayment protection.They are, therefore, of no interest to investors seeking short-duration mortgage-backed assets