问题如下：
Tim, a junior analyst in a securities company, is preparing a strategy report. By analyzing the real estate industry, he found 4 closely related stocks:
Company A is relatively undervalued by 10%;
Company B is relatively undervalued by 5%;
Company C is relatively overvalued by 8%;
And company D is relatively undervalued by 7%.
According to the information above, if Tim wants to use the pairs-trading strategy, which of the following is correct?
选项：
A.Short sell company A’s stock and short sell company B’s stock;
B.Buy company C’s stock and short company B’s stock;
C.Short sell company C’s stock and buy company D’ stock.
解释：
C is correct.
考点：考察对relative valuation方法的理解，以及根据relative value做pairs-trading strategy.
解析：根据pairs-trading strategy利用两个高度相关但股票价格却偏离的股票；购入相对被低估的股票，卖出相对被高估的股票。
老师，pairs-trading strategy中一买一卖的两个股票必须高度相关吗？为什么？谢谢。
