The correct answer is the option (d) the increase of carbon dioxide.
The increase of carbon dioxide in the earth's early atmospheric conditions made the aquatic dwelling organisms to adapt into terrestrial dwellers. Volcanic eruptions released a few gases, of which, carbon dioxide was abundantly released. It is a vital requirement for all living organisms. The first terrestrial plants appeared which used the carbon dioxide for the synthesis of food by the process of photosynthesis. Thus, this continuous availability of carbon dioxide helped the land dwelling plants to evolve. This increased the oxygen content in the atmosphere which made the animals to evade the terrestrial habitat.
The build up of ozone was not an earth's early atmospheric condition and the stromatolites were the sedmientary rock layers of water bodies like oceans. The formation of rust on the earth's crust did not help the land dwelling animals to evolve.
Thus, the increase in the carbon dioxide helped the land dwelling oragnisms to evolve.
