Answer: Option A. "ethylene oxide"
Step-by-step explanation:
Antiseptics are defined as an antimicrobial substances which are applied on living tissues or skin that helps in reducing infection without causing any harm to living cells.
Ethylene oxide is flammable colorless gas that have narcotic effect over living cells. ethylene oxide is used as sterilizing agent and pesticide. Ethylene oxide has the ability to damage DNA which makes it an effective sterilizing but counts for harmful effects on living tissues.
Hence, the correct option is A.