An analyst collects the following set of ten returns of a firm from the past: 2.2 percent, 6.2 percent, 8.9 percent, 9.3 percent, 10.5 percent, 11.7 percent, 12.3 percent, 14.1 percent, 15.3 percent, and 18.4 percent. What value is closest to the geometric mean return of this firm()

A. 9.62%

B. 10.80%

C. 10.89%

发电机反时限负序电流保护的动作时限是（）。

A.无论负序电流大或小，以较长的时限跳闸

B.无论负序电流大或小，以较短的时限跳闸

C.当负序电流大时以较短的时限跳闸，当负序电流较小时以较长的时间跳闸

D.当负序电流小时以较短的时限跳闸，当负序电流较大时以较长的时间跳闸