Which Process Probably Evolved First on the Ancient Planet Earth

Multiple Choice

Which process probably evolved first on the ancient Planet Earth - photosynthesis or cellular respiration?

A) Photosynthesis because it provided atmospheric oxygen that facilitated evolution of aerobic organisms.
B) Cellular respiration because carbon dioxide from citric acid cycle provided source of carbon fixation for photosynthesis.
C) Photosynthesis because there was plenty of light and CO₂ in the atmosphere for carbon fixation but no organic molecules to use as carbon and energy sources.
D) Cellular respiration because it is the universal metabolic pathway.