What should you do if it is necessary to drive through water on the roadway?

Answer: B — Lightly apply brakes to reduce water in brake drums

When driving through water on the roadway, it is important to lightly apply brakes to reduce the amount of water in the brake drums. This will help prevent the brakes from becoming wet and less effective. Option A, increasing speed to create a wave, is incorrect because it can cause water to splash into the engine and cause damage. Option C, doing nothing special, is also incorrect because driving through water should be treated as a unique situation and requires special precautions. Option D, turning on hazard lights and stopping, is incorrect because it is important to keep moving through the water with caution to avoid stalling the engine.