问题如下：
In which of the following cases did the firm default due to fraud?
选项：
A. Metallgesellschaft Refining and Marketing
B. Northern Rock Bank
C. Victor Niederhoffer
D. None of the above
解释：
C is correct.None of the above
The fraud examples included Barings Bank and Enron.
老师好，这道题的正确答案应该是D。