This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Classification of carbohydrate, Subject name: Biochemistry
[{'content': 'Enantiomers are isomers that differ in structure at which carbon : \nSelect and explain. \nA. Last Carbon, B. First Carbon, C. Penultimate Carbon, D. Carbonyl Carbon', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Enantiomers have different -H and -OH orientation around the penultimate carbon /2nd last carbon/Reference carbon. E.g-. D-and L-Glyceraldehyde. Also known as Mirror images of each other.', 'role': 'assistant'}]