二类高层建筑与耐火等级为三、四级的丙类厂（库）房建筑之间的防火间距应不小于()
A.25m
B.20m
C.15m
D.10m
参考答案：B
道口栏杆开放后与道路边缘垂直高度不少于（）。
A.1米
B.2米
C.3米
D.3.5米
The mean monthly return on U.S. Treasury bills ( T - bills) is 0.42 percent. The mean monthly return for an index of small stocks is 4.56 percent, with a standard deviation of 3.56 percent. What is the Sharpe measure for the index of small stocks（）
A. 10.60%.
B. 16.56%.
C. 1.16%.
