Explain this chart.

Discount Bonds Contract rate is lower that the m rat bond is sold at a price less than the par value Premium Bonds Contract rate is higher that the market rate; bond is sold at a price higher than the par value bond issuer receives less cash at issuance than the par issuer receives more cash at issuance than the par value bond issuer must pays back the par value at maturity bond issuer must pays back the par value at maturity total bond interest expense is computed by adding total bond interest expense is computed by bond discount to the interest payment over the subtracting bond premium from sum Of we amortize only the discount amount we amortize only the premium amount nually interest cash payment is paid based on semiannually inierest cash payment is contract rate contract rate decrease in discount on bonds payable and increase in decrease in unamortized bond premium and decrease the bond's carrying value in carrying value