Final answer:
Production of O₂ (Option A) does not occur during the Calvin cycle. This is a part of the light-dependent reactions of photosynthesis. Carbon fixation, regeneration of RuBP, use of ATP, and oxidation of NADPH all occur within the Calvin cycle.
Step-by-step explanation:
Your question is about the Calvin cycle and what does not occur during this process. The options were the production of O₂, carbon fixation, regeneration of RuBP, use of energy from ATP, and oxidation of NADPH. During the Calvin cycle, oxygen (O₂) is not produced; instead, that occurs during the light-dependent reactions of photosynthesis. What happens in the Calvin cycle is carbon fixation (when CO₂ is attached to RuBP), reduction (where energy from ATP and NADPH is used to produce G3P), and then regeneration of RuBP so the cycle can continue. To summarize, production of O₂ (Option A) does not occur during the Calvin cycle; it is associated with the light-dependent reactions.