Below are the yields and durations for three 15-year bonds. The three coupon rates are 0%, 3.5%, and 7%. Which coupon rate belongs to which bond? What is the shape of the term structure of spot rates underlying the valuation of these bonds?

Bond #1: yield=3.50% duration=11.59

Bond #2: yield=3.50% duration=14.75

Bond #3: yield=3.50% duration=10.26