The correct answer is C: Take precautions to ensure that the antenna cannot be pointed in their direction when they are present. What should be done if evaluation shows that a neighbor might experience more than the allowable limit of RF exposure from the main lobe of a directional antenna is to take precautions to ensure that the antenna cannot be pointed in their direction when they are present. You must prevent the antenna from being aimed at neighbors when they're nearby. For amateur radio operators, this is required for compliance. Understanding this helps ensure neighbor safety.