The Value Line index is an equally weighted geometric average of the return of about 1700 firms. What is the value of an index based on the geometric average returns of three stocks, where the returns on the three stocks during a given period were 20% , -10%, and 5% 9（）

A. 4.3%.

B. 5.0%.

C. 11.7%.

电路中，参考点选好以后，要计算某点的电位时，必须选择由该点至参考点的路径，其路径可以任意选取。