Which of the following statements does not illustrate how firms can fail to correctly monitor and manage risk on an ongoing basis?
　　A. Some securities have complex relationships with market variables such as interest rate changes.
　　B. Portfolio risk profiles do not change over time.
　　C. Not having an adequate incentive structure.
　　D. Not having an adequate culture that promotes effective risk management.
　　Answer:B
　　Portfolio risk profiles can change even during the absence of trading. The properties of some securities can change for several reasons (e.g., changes in interest rates, embedded derivatives).