为什么选C啊

问题如下：

Which of the following market indexes is likely to be reconstituted most frequently? An index that is designed to measure:

选项：

A.

real estate returns

B.

growth stock prices

C.

commercial paper yields

解释：

An index of commercial paper yields needs to be reconstituted frequently because its constituent securities need to be replaced when they mature and commercial paper matures in 270 days or less. Indexes of growth stocks and real estate are likely to be reviewed periodically to confirm that their constituent assets still meet the qualifications to be included in the index.