问题如下：
Which of the following derivatives is classified as a contingent claim?
选项：
A. Futures contracts
B. Interest rate swaps
C. Credit default swaps
解释：
C is correct.
A credit default swap (CDS) is a derivative in which the credit protection seller provides protection to the credit protection buyer against the credit risk of a separate party. CDS are classified as a contingent claim.
A is incorrect because futures contracts are classified as forward commitments. B is incorrect because interest rate swaps are classified as forward commitments.
请问B为什么不是呢？
