The ratio of CO₂, NADPH₂, and ATP molecules required for one Calvin cycle is

Explanation

The Calvin cycle, also known as the light-independent reactions of photosynthesis, uses 3 molecules of CO₂, 6 molecules of NADPH, and 9 molecules of ATP to produce one molecule of glyceraldehyde-3-phosphate (G3P), which can then be used to form glucose and other carbohydrates. Option B is correct, as it reflects these stoichiometric needs. Option A suggests a smaller scale of reaction that is not reflective of the cycle's full completion. Options C and D suggest larger scales than needed for a single cycle.