This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'During conversion of glycerol to pyruvic acid, the first glycolytic intermediate to form is: \nSelect and explain. \nA. 2 - phospho glyceric acid, B. 3 - phospho glyceric acid, C. 3 - phospho glyceraldehyde, D. Dihydroxy acetone phosphate', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]