单选题 One reason that criticism has been leveled at derivatives and derivatives markets is that:

A、 derivatives have too much default risk.
B、 markets for derivatives seldom function efficiently like a stock exchange.
C、 they are complex instruments and sometimes hard to understand.

【正确答案】 C

【答案解析】The fact that derivative securities are sometimes complex and often hard for non-financial commentators to understand has led to criticism of derivatives and derivative markets.