Financial derivatives contribute to market completeness by allowing traders to do all of the following EXCEPT :()
A. increase market efficiency through the use of arbitrage.
B. hedge positions in other assets and engage in high risk speculation.
C. narrow the amount of trading opportunities to a more manageable range.
参考答案：C
解析：
Financial derivatives increase the opportunities to either speculate or hedge on the value of underlying assets. This adds to market completeness by increasing the range of identifiable payoffs that can be used by traders to fulfill their needs. Financial derivatives such as market index futures can also be easier and cheaper than trading in a diversified portfolio, thereby adding to the opportunities available to traders.