A 7% general obligation bond is issued with 20 years to maturity. A customer buys the bond on a 7.50% basis. The bond contract allows the issuer to call the bonds in 5 years at 102 1/2, with the call premium declining by 1/2 point a year thereafter. The bond is puttable in 5 years at par. The price of the bond to a customer would be calculated based on the:

A. 5 year call at 102 1/2
B. 5 year put at 100
C. 10 year call at 100
D. 20 year maturity