Consider the following CMO: - Tranche A issued for $12 million with a coupon of 6.5% - Tranche B issued for $4 million with a coupon of 6.5% - Z-Tranche issued for $4 million with a coupon of 6.5% The securities are backed by a pool of fully amortizing 30-year fixed rate mortgages with WAC equal to 6.5% and monthly payments. There is assumed to be a 5% CPR in this pool and no servicing fee. What does this graph represent?

A. Principal payment on each tranche

B. Interest payment on each tranche

C. Remaining balance on each tranche

D. Cash flow to each tranche