问题如下：
Based on Exhibits 3 and 4, the price for Bond D is closest to:
选项：
A.97.4785.
B.103.3230.
C.106.3230.
解释：
B is correct.
Time 2 node values:
Upper node: 0.5 × [(103/1.027183) + (103/1.027183)] + 3 = 103.2743.
Middle node: 0.5 × [(103/1.016487) + (103/1.016487)] + 3 =104.3294.
Lower node: 0.5 × [(103/1.01) + (103/1.01)] + 3 = 104.9802.
Time 1 node values:
Upper node: 0.5 × [(103.2743/1.028853) + (104.3294/1.028853)] + 3= 103.8908.
Lower node: 0.5 × [(104.3294/1.0175) + (104.9802/1.0175)] + 3 =105.8548.
Time 0 node value:0.5 × [(103.8908/1.015) + (105.8548/1.015)] = 103.3230.
Therefore, the price of the bond is 103.3230.
Bond D的maturity是三年，但是答案却是直接用两年的二叉树折。为什么不是先算出3年的二叉树，再折现算出price of bond D呢？
