问题如下图：
选项：
A. 
B. 
C. 
D. 
解释：
请问这题的考点是什么？没明白题意。
GerarKuper is moling the number of operationrisk loss events thcoulaersely impaBank Ain 2010. He expects the number of operationrisk loss events for the yeto relatively small. Whitype of stribution is he least likely to use? Normstribution Binomistribution Negative binomistribution Poisson stribution A is correct. The last three stributions require the number n to positive, whiis not the case for the normstribution. 请问Negative binomistribution指怎样的分布呢？
这题考的知识点是哪一章节？另外哪里说了n也可以是负数？谢谢！
