问题如下：
Even though risk managers cannot eliminate model risk,
there are many ways managers can protect themselves against model risk. Which
of the following statement about managing model risk is correct?
选项：
A.Models should be test against known problems.
It is not advisable to estimate model risk using
simulations.
Complex models are generally preferable to simple
models.
Small discrepancies in model outputs are always
acceptable.
解释：
One way to protect against model risk is to test a
model against known problems. It is always a good idea to check a model against
simple problems to which one already knows the answer, and many problems can be
distilled to simple special cases that have known answers. If the model fails
to give the correct answer to a problem whose solution is already known, then
this indicates that there is something wrong with it.
老师好，能否讲一下选项B，模型风险为什么要用simulation来估计？
