What should a driver do when they see a sign "CHECK BRAKES"?

When a driver sees a "CHECK BRAKES" sign, the appropriate action is to gently press the brake pedal to ensure that it is functioning correctly. This sign indicates that the driver should verify that their braking system is in good working condition, as brakes are crucial for safe driving. By gently pressing the brake pedal, the driver can assess its response and effectiveness, which may signal if any adjustments or repairs are needed before continuing their journey.

The other options involve risky behaviors that can compromise safety. Pressing the gas and abruptly applying the brake could lead to loss of control over the vehicle or cause sudden stops that may endanger the driver and others on the road. Heading for the innermost lane and stopping without evaluating the brakes does not directly address the issue at hand and could create a hazardous situation if the driver is not aware of their braking condition. Hence, the recommended course of action is to check the brakes properly to ensure safe operation of the vehicle.