A driver who consistently demonstrates fair control is likely to require which of the following?

The answer is that a driver who consistently demonstrates fair control is likely to require additional training. This option is correct because "fair control" indicates that the driver's skills may not be at an optimal level needed for safe and effective driving. Additional training is often necessary to help improve their ability to handle various driving situations, enhance their overall driving skills, and build confidence behind the wheel.

Increased supervision, while it might seem relevant, would not directly address the need for skill improvement. Certification is typically a formal acknowledgment of proficiency, which may not be warranted if the driver only shows fair control. Retesting might be considered for various reasons, but it does not specifically focus on skill enhancement like additional training would. Therefore, additional training directly addresses the need to improve the driver's control and safety skills on the road.