B is the correct answer
When you vote, that's the best way to "participate" in the democratic system
Answer:
Hair
Explanation:
The scientist predict that the contamination occurred several months ago. Under normal circumstances, most organisms would no longer have a trace of exposure in their urine or blood after 3 months. If the organisms exposed to the radioactive three months ago and do not come near that area again within 3 months, the scientist wouldn't be able to identify it.
But, if that substance got into their hair, it will last way longer than that. Hair Analysis is very common to be used among forensic toxicologist to identify contamination that occurred months because of this.
France, Switzerland, and Germany.