This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Toxicology - 1, Subject name: Forensic Medicine
Smell of bitter almonds is seen in poisoning with: 
Select and explain. 
A. Phosphorus, B. Hydrocyanic acid, C. Nitric acid, D. Oxalic acid
B: Hydrocyanic acid
Answer: B: Hydrocyanic acid 
Explanation: Smell about mouth & Nose- 1) Garlic-like- Phosphorus, Arsenic, Organophosphates Thallium, Selenium, Dimethylsulphoxide. 2) Sweetish or fruity- Ethanol, Chloroform, Nitrites. 3) Acrid (pear like)- Paraldehyde, Chloral hydrate. 4) Rotten eggs- Hydrogen Sulphide, Mercaptans, Disulfiram. 5) Fishy or musty- Zn Phosphide, Aluminium phosphide 6) Bitter almonds- Cyanides, HCN 7) Shoe polish- Nitrobenzene 8) Burnt rope- Marijuana (Cannabis) 9) Vinegar: Acetic acid