The key focus of the article is a rat called HeroRAT that was used to sniff out buried explosives in Cambodia. So the article is about Rats and Land Mines.
HeroRat, also known as Magawa, is the name given to an African giant rat in Cambodia (which was six years old as of 2020) that was able to save many lives by detecting thirty-nine landmines.
It also detected over twenty-seven items in Cambodia that hadn't exploded. The correct answer, thus, is D.
See the link below to learn more about Rats and Land Mines:
https://brainly.com/question/26368251