'Perform scenario analysis retrospectively' is not a correct feature of risk appetite and risk tolerance statements according to the 4th principle of operational risk management. These statements are meant to be forward-looking and subject to scenario and stress testing. This means they should anticipate future scenarios and risks, rather than analyzing past scenarios retrospectively. The purpose of these statements is to guide the bank's future actions and decisions regarding operational risks, so they need to be proactive and forward-thinking, not retrospective.

Choice A is incorrect. The risk appetite and tolerance statements should indeed be easy to communicate and understand. This ensures that all stakeholders, including the board, management, employees, and even external parties such as regulators or investors have a clear understanding of the bank's approach to operational risk.

Choice B is incorrect. Providing reasons for taking or avoiding certain operational risks is an important feature of these statements. It helps in aligning the bank's strategic objectives with its operational risk management framework.

Choice C is incorrect. Being forward-looking and subject to scenario and stress testing are key characteristics of these statements according to the 4th principle of operational risk management. This allows banks to anticipate potential future risks and prepare accordingly.