This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Histamine, 5-HT and PGs, Subject name: Pharmacology
Prostaglandins are obtained from:- 
Select and explain. 
A. Stearic acid, B. Arachidonic acid, C. Linoleic acid, D. Linolenic acid
B: Arachidonic acid
Answer: B: Arachidonic acid 
Explanation: NOTE:-Arachidonic Acid is a 20 carbon fatty acid. No.of double bonds in Arachidonic acid =4 Key points to Remember Linoleic Acid- Most essential Fatty Acid. Richest source of linoleic Acid - Safflower oil. Richest source of Arachidonic Acid - Safflower oil. Richest source of Linolenic Acid - Flaxseed oil.