Synonym of LETHAL

Answer: Option B

Unlawful : not conforming to, permitted by, or recognized by law or rules.
Deadly : causing or able to cause death.
Sluggish : slow-moving or inactive.
Smooth : having an even and regular surface; free from perceptible projections, lumps, or indentations.
Lethal : sufficient to cause death.

Synonym of Lethal is Deadly