This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Forensic Medicine
An adult came to casualty with complaints of rapid hea rate. On examination everything else was normal except for episodic tachycardia and occasional extra-systole and amblyopia. Which of the following is the cause of it? 
Select and explain. 
A. Nicotine, B. Cannabis, C. Atropine, D. Cocaine
A: Nicotine
Answer: A: Nicotine 
Explanation: Answer- A. NicotineNicotine chronic poisoning can lead to cough, wheezing, dyspnoea, anorexia, vomiting, diarrhea, anaemia, faintness,tremors, impaired memory, amblyopia, blindness, irregularities, of the hea with extra-systoles and occasionally attacks pain suggesting angina pectoris.