Choose your answer before opening the explanation. This is a learning exercise, not a competency assessment.
A suspect patch appears in one room. The best first action is:
- Paired readings at the patch and a clean spot in the same room
- Spray the room
- Increase the temperature
- Empty the room
See the answer and why
Paired readings at the patch and a clean spot in the same room Another reading is always reversible; a spray is not.

