The correct answer is D. Cyanobacteria.
Explanation
Cyanobacteria are a group of bacteria that has the particular capacity of oxygenic photosynthesis, that is, the cyanobacteria produce oxygen using water. This contributed to the accumulation of oxygen in the atmosphere close to two thousand and seven hundred million years ago. This contribution caused the improvement of the biosphere in the Earth with the help from the oxygen produced by Cyanobacteria. Additionally, cyanobacteria are evidence of early forms of life in the universe considering these are one of the oldest organisms in Earth that lead to more complex life due to the oxygen they provided to the atmosphere. So, the correct answer is D. Cyanobacteria
