Answer: Option A.
Photoautotrophs- nitrogen.
Step-by-step explanation:
Photoautotroph organism uses light energy as energy source.
Photoautotrophs are organisms that uses light energy from sunlight with carbon dioxide and water in conjunction with green pigments, chlorophyii present in them to manufacture or produce carbohydrates or glucose which is use for cellular processes.
Green plants and photosynthetic bacteria are examples of photoautotroph.