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
Rate limiting step in HMP shunt ? 
Select and explain. 
A. Glucose-6-phosphate - 6-phosphogluconolactone, B. 6-phosphogluconolactone - 6-phosphogluconate, C. 6-phosphogluconate - Ribulose-5-phosphate, D. Ribulose-5-phosphate - Xylulose-5-phosphate
A: Glucose-6-phosphate - 6-phosphogluconolactone
Answer: A: Glucose-6-phosphate - 6-phosphogluconolactone 
Explanation: Ans. A. Glucose-6-phosphate - 6-phosphogluconolactone