Which process occurs only in autotrophic organisms? Calvin cycle chemiosmosis Krebs cycle proton pump mechanism

The answer to this question should be: Calvin cycle

Calvin cycle is a chemical reaction that was done in the chloroplast of a plant. This is one of the reactions in photosynthesis. In Calvin cycle, carbon dioxide and water will be used to make carbohydrates (glucose). This reaction is forming energy using the sunlight so only autotrophic organism capable that will be able to do it.