Which substance can impair driving ability besides alcohol?

The correct answer recognizes that a wide array of substances can impair driving ability, including prescription medications, over-the-counter drugs, and illegal drugs. Each of these categories may contain ingredients that can affect motor skills, judgment, reaction times, and overall cognitive function, which are critical for safe driving.

For instance, many prescription medications come with warnings about drowsiness or impaired motor control, particularly those classified as sedatives or tranquilizers. Likewise, over-the-counter medications such as antihistamines can lead to similar impairments due to their sedative effects. Illegal drugs, of course, are well-known for their potential to significantly alter a person's capacity to operate a vehicle.

The other options do not encompass the full spectrum of substances that can impair driving. While illegal drugs can impair driving, limiting the answer to only those disregards the significant impact that legal medications and even common over-the-counter drugs can have on driving ability. Caffeine, while it can have stimulating effects, typically does not impair driving in the same way as other substances and may even enhance alertness in moderation. Food supplements are generally not associated with impairments related to driving unless they contain specific ingredients that affect mental or physical capabilities.