Synonym of INTERNECINE

Answer: Option A

Deadly : causing or able to cause death.
Foolhardy : recklessly bold or rash.
Stealthy : behaving or done in a cautious and surreptitious manner, so as not to be seen or heard.
International : existing, occurring, or carried on between nations.
Internecine : destructive to both sides in a conflict.

Synonym of Internecine is Deadly