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 2 of gaining passive exposure, an advantage of Approach 1 is that it:
选项：
A.reduces the need for frequent rebalancing
limits the need to purchase bonds that are thinly traded
provides a higher degree of portfolio risk diversification
解释：
C is correct.
Approach 1 is a full replication approach, whereas Approach 2 follows an enhanced indexing strategy. Both full replication and enhanced indexing can be used to establish a passive exposure to the bond market. Under full replication, the manager buys or sells bonds when there are changes to the index. The larger number of index constituents associated with full replication provides a higher degree of risk diversification compared with an enhanced indexing strategy
B答案是什么意思？
