参考答案：B

解析：
An index is a statistical composite representing the value of all stocks in a certain market segment. It’s presented as one simple number so investors can track trends in that segment. The broader the index, the more representative it is of the entire stock market. The Dow Jones Industrial is an average of 30 of the most widely held stocks. The S&P 500 Index combines the prices of 500 widely held stocks chosen by Standard and Poor’s. The Russell 2000 includes 2000 small-company stocks; the Wilshire 5000 includes both small-and large-company stocks and is weighted to represent all U.S.-headquartered securities.

[分析]： 特定信息的找寻和判断。
根据题干中提到的特定信息找寻原文，发现“The Russell 2000 includes 2000 small-company stocks”，由此可见，选项B的说法符合题意，是正确答案。
[解题关键] 找寻特定信息要迅速排除干扰项。本题中各种专有名词和数字的信息量颇大，需要迅速排除这些信息的干扰，才能快速准确地找到正确答案。