This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of lipid, Subject name: Biochemistry
[{'content': 'Essential fatty acid \nSelect and explain. \nA. Linoleic acid, B. Palmitoleic acid, C. Oleic acid, D. Arachidonic acid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Linoleic and a-linolenic acids are the only fatty acids known to be essential for the complete nutrition of many species of animals, including humans, and are termedthe nutritionally essential fatty acids. In most mammals, arachidonic acid can be formed from linoleic acid.Ref: Harper 9e pg: 238', 'role': 'assistant'}]