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': 'Number of -OH groups in ribose: \nSelect and explain. \nA. 4, B. 5, C. 6, D. 2', 'role': 'user'}, {'content': 'Answer: A \nExplanation: option a : Number of -OH groups in ribose is 4 General rule : Number of -OH groups are always one less than the number of carbons in carbohydrates Glucose (6C) has 5 -OH groups. Ribose (5C) has 4 -OH groups. MONOSACCHARIDES No of C atoms Generic name Example (Ald) No. of OH groups 3 Trioses Glyceraldehyde 2 4 Tetroses Erythrose 3 5 Pentoses RiboseXylose (Epimer of Ribose) Arabinose 4 6 Hexoses GlucoseGalactose Mannose 5', 'role': 'assistant'}]