问题如下：
Compton notes that SD&R generally uses actively managed portfolios designed to earn a return in excess of the benchmark portfolio. For clients interested in passive exposure to fixed-income instruments, SD&R offers two additional approaches.
Approach 1：Seeks to fully replicate the Bloomberg Barclays US Aggregate Bond Index
Approach 2：Follows an enhanced indexing process for a subset of the bonds included in the Bloomberg Barclays US Aggregate Bond Index. Approach 2 may also be customized to reflect client preferences
Relative to Approach 1 of gaining passive exposure, an advantage of Approach 2 is that it:
选项：
A.minimizes tracking error
requires less risk analysis.
is more appropriate for socially responsible investors.
解释：
C is correct.
Enhanced indexing is especially useful for investors who consider environmental, social or other factors when selecting a fixed-income portfolio. Environmental, social, and corporate governance (ESG) investing, also called socially responsible investing, refers to the explicit inclusion or exclusion of some sectors, which is more appropriate for an enhanced index strategy relative to a full index replication strategy. In particular, Approach 2 may be customized to reflect client preferences.
想知道为什么A不对，Enhanced indexing 不是有个优点是minimize tracking error么，在ppt155页
