Answer:
D). Working in a containment zone is very dangerous.
Step-by-step explanation:
The central or overarching idea that the author intends to convey through the given excerpt is that 'Working in a containment zone is fatal' as such a zone is 'full of the pressure...to get inside your suit.' The language that the author has chosen to describe the environment of the zone and the phrases like 'amplified unknown hot agent; high-hazard work' clearly substantiate this key idea that the author is highlighting. He calls it 'gray-zone' which emphasizes his idea and he also says 'people went into Level 4 which is like a spacewalk' that discloses the gravity of hazards faced by people working there. Thus, option D is the correct answer as it reveals the key idea of threats and dangers of working containment zones.