This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Forensic Medicine
A FACTORY WORKER PRESENTED WITH TREMORS AND PERSONALITY CHANGES ON EXAMINATION HIS HANDS SHOWN BELWO , WHAT IS THE DIAGNOSIS? 
Select and explain. 
A. MERCURY POISONING, B. LEAD POISONING, C. ARSENIC POISONING, D. COCAINE POISONING
A: MERCURY POISONING
Answer: A: MERCURY POISONING 
Explanation: Mercury Poisoning Acute effect * By ingestion: local corrosive effects; nausea, vomiting, severe abdominal pain, chemical colitis, renal damage * By inhalation: chemical pneumonitis, pulmonary edema Chronic effect * Classic symptoms: tremor, gingivitis, erethism (greek erethismos = irritate) * Renal & CNS damage * Minamata disease - neurological syndrome caused by severe mercury poisoning REF : NARAYANA REDDY TOXICOLOGY