问题如下：
Which of the notes regarding the Elmer Fund is correct?
选项：
A.Only Note 4
B.Only Note 5
C.Both Note 4 and Note 5
解释：
A is correct. For passively managed portfolios, management fees are typically low because of lower direct costs of research and portfolio management relative to actively managed portfolios. Therefore, Note 4 is correct.
Note 5 is incorrect because the predictability of correlations is uncertain.
那这个和加入的bond类型有关系吗？如果是更像股票的垃圾债，结论和投资级别债券一样吗？还是说只要是bond就从【长期来看具有分散效果；短期一般有分散效果，但特殊情况如经济危机下性质一样，加大风险】这个维度考虑吗？
