In which of the following steps, ATP is released?: (A) Phosphoenol pyruvate to pyruvate, (B) Glyceraldehyde-3-phosphate to 1,3 bisphosphoglycerate, (C) Fructose-6-phosphate to fructose 1,6 bisphosphate, (D) Glucose to glucose-6-phosphate
Answer is A. Steps releasing ATP at the level of substrate:

1, 3 Bisphosphoglycerate to 3-Phosphoglycerate (1, 3 Bisphosphoglycerate Kinase)
Phosphoenolpyruvate to Pyruvate (Pyruvate Kinase)
Succinyl CoA to Succinate (Succinate Thiokinase)