请问为什么不选C 问题如下图：
选项：
A. 
B. 
C. 
D. 
解释：
investor hsolfault protection on the most senior tranche of a C. If the fault correlation creases unexpectey, assuming everything else is unchange the investor’s position will Gain value sinthe probability of exercising the protection falls. Lose value, sinthe investor^ protection will gain value. Neither gain nor lose value sinonly expectefault losses matter ancorrelation es not affeexpectefault losses. It pen on the pricing mol useanthe market contions. ANSWER: A The value of the senior tranche pen on the fault correlation. If this goes wn, the stribution of losses will more versifie or tighter, whimakes it less likely thlosses will wipe out the lower tranches. Hence, the value of senior tranche goes up. Selling fault protection is equivalent to being long the senior tranche, whicreates a gain unr these contions. fault correlation指的是不同层次之间的还是senior tran内部的correlation呢？
investor hsolfault protection on the most senior tranche of a C. If the fault correlation creases unexpectey, assuming everything else is unchange the investor’s position will Gain value sinthe probability of exercising the protection falls. Lose value, sinthe investor^ protection will gain value. Neither gain nor lose value sinonly expectefault losses matter ancorrelation es not affeexpectefault losses. It pen on the pricing mol useanthe market contions. ANSWER: A The value of the senior tranche pen on the fault correlation. If this goes wn, the stribution of losses will more versifie or tighter, whimakes it less likely thlosses will wipe out the lower tranches. Hence, the value of senior tranche goes up. Selling fault protection is equivalent to being long the senior tranche, whicreates a gain unr these contions. 看了之前的问答，还是不明白，麻烦再给下 1) 从哪看出来标的物降价了？题目不是说fault correlation降低么。 2) sell fault protection是什么角色，怎么理解，为什么说等于long senior？
