问题如下：
The equal weighting index needs to be rebalanced:
选项：
A.periodically.
B.frequently.
C.infrequently.
解释：
When an index is calculated by using the equal-weighting method, changing market prices lead to inequality of initial equal weights and therefore need to be rebalanced.
这道题为什么不选A，定期调整权重，通常不是按季度调整权重
