This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Forensic Toxicology - Concepts, Statutes, Evidence, and Techniques, Subject name: Forensic Medicine
A factory worker presented with tremors, personality change and a blue line in gum. Probable diagnosis is chronic poisoning with: 
Select and explain. 
A. Lead, B. Mercury, C. Arsenic, D. Thallium
B: Mercury
Answer: B: Mercury 
Explanation: Ans. (B). Mercury.Mad hatter disease is an occupational disease among hatmakers, caused by chronic mercury poisoning.Mental confusin, emotional disturbances, and muscular weakness, Intentional tremor (Hatter's shakes)