问题如下：
Which of the following statements regarding commodity derivatives is correct?
选项：
A. The primary commodity derivatives are futures.
B. Commodities are subject to a set of well- defined risk factors.
C. Commodity traders and financial traders today are distinct groups within the financial world.
解释：
A is correct. The primary commodity derivatives are futures, but forwards, swaps, and options are also used. B is incorrect because the commodity market is extremely large and subject to an almost unimaginable array of risks. C is incorrect because commodity and financial traders have become relatively homogeneous since the creation of financial futures. Historically, commodity traders and financial traders were quite different groups, and there used to be a tendency to think of the commodity world as somewhat separate from the financial world.
请问这题的C为什么错？
