问题如下：
Which of the following statements about shortcomings of “VCV Matrix with Sample Statistics” is incorrect？
选项：
A. The sample VCV method can be used if the number of assets exceeds the number of observations.
B. This method does not address the issue of imposing cross-sectional consistency.
C. Given typical sample sizes, this method is subject to substantial sampling error.
解释：
A is correct.
解析：
对于“VCV Matrix with Sample Statistics”这种方法，在给定典型的样本量下，该方法存在较大的抽样误差。而且这个方法没有解决强制横截面一致性的问题。所以BC选项都是该种方法的缺点。
如果资产的数量超过观察值，那么就不能使用样本VCV方法，所以A选项的说法不准确。A入选。
资产的数量，超过观察值。这句话里。老师能用一个场景说一下，谁是观察值，谁是资产数量吗
