问题如下：
Which of the following most correctly describes the sample of equity ratios of 50 U.K. banks at fiscal year 2017?
选项：
A.Interval estimate.
B.Cross-sectional data.
C.Time-series data.
解释：
B is correct.
Because the data for the sample are collected at the same point of time, So it is the example of the cross-sectional data.
为什么不能选A，取值范围【0，100%】。
