A driver finishes drinking heavily at 1 a.m., sleeps six hours, and feels alert over coffee at 7 a.m. before a morning drive. What is the risk?

Why B is correct

The liver's rate does not care whether the drinker is asleep, and a heavy evening's alcohol can easily outlast a night's sleep: by the arithmetic of elimination, a large quantity at 1 a.m. can still be measurably present at 8 a.m. Alertness is the trap — sleep restores wakefulness, which is exactly the faculty people use as a sobriety test, while the alcohol sits in the blood unchanged. Morning-after impaired driving is a recurring enforcement finding precisely because the driver's self-assessment is honest and wrong: they feel like themselves, and they are not.

Why the other options are wrong

A. None; six hours of sleep eliminates alcohol faster than remaining awake

Sleep does not metabolise anything; it suspends the drinker while the liver works at the same pace it would at a bar stool. The six hours remove exactly what the liver removed, not a minute more.

C. Only the risk of drowsiness, not of alcohol

The alcohol risk is real and independent of the drowsiness risk. A driver can solve the fatigue problem with a night's sleep and still fail a breath test at breakfast, which is the specific scenario the question describes.

D. No risk, because alcohol leaves the body entirely during sleep

Total elimination during sleep would require the liver to have finished before the drinking ended. Heavy drinking saturates that schedule by hours; 'entirely during sleep' is the wishful version of the arithmetic.

On the road

A wedding, a 1 a.m. finish, and a 7:30 a.m. drive to the airport over coffee and confidence. The 9 a.m. checkpoint on the airport road exists because that profile is common enough to staff for: rested, alert, over the limit. The driver who 'slept it off' learns the liver does not keep party hours — the breathalyser does.

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