Answer:
The correct answer would be 3-PGA (3-phosphoglyceric acid).
During carbon fixation of the Calvin cycle, one molecule of carbon dioxide combines with ribulose-1,5-bisphosphate (RuBP) which is a five-carbon molecule.
Thus it leads to the formation of a six carbon molecule which is divided into two molecules each with three carbons that is, two molecules of 3-phosphoglyceric acid.
The entire reaction is catalyzed by the enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO).
Molecules of 3-phosphoglyceric acid then undergo reduction to produce glyceraldehyde-3-phosphate (G3P) with the help of ATP and NADPH.
Some molecules of G3P are used to make glucose and some are used to regenerate RuBP with the help of ATP.