A $$128,000$ trust is to be invested in bonds paying $6\%,CD$ s paying $5\%,$ and mortgages paying $7\%.$ The sum of the bond and $CD$ investment must equal the mortgage investment. To earn an $$7900$ annual income from the investments, how much should the bank invest in bonds?

$$20,000$

$$22,000$

$$64,000$

$$42,000$