Which of the following is the BEST course of action if the business activity residual...

If the residual risk of the business activity is lower than the acceptable risk level, it means that the existing controls are effectively mitigating the identified risks. In this case, the best course of action is to monitor the effectiveness of the controls and ensure they remain effective. The information security manager should review and test the controls periodically to ensure that they continue to provide adequate protection. It is also essential to update the risk assessment framework to reflect changes in the business environment or risk landscape.