NO.PZ2019012201000061
问题如下：
Knight foresees a possible scenario in which the investment universe for the Heydon Quant Fund is unchanged but a new factor is added to its multifactor model. Knight asks Nowacki whether this scenario could affect the fund’s investment-style classifcations using either the returns-based or holdings-based approach. The most appropriate response to Knight’s question regarding the potential future scenario for the Heydon Quant Fund is:
选项：
A. only the returns-based approach
B. only the holdings-based approach
C. both the returns-based approach and the holdings-based approach
解释：
C is correct. Because the Heydon Quant Fund would be changing its facto rmodel by adding a new factor, the correlations of the fund’s returns with the factors would likely change and the returns-based style would change. Even though the investment universe is unchanged, the portfolio holdings would likely change and the holdings-based style classifcation would also will be affected.
可以简单解释一下return-based和holding-based吗？
