Answer:
Option (A)
Step-by-step explanation:
In the primitive world, about 3 billion years back, there has been a sudden increase in the amount of oxygen gas in the atmosphere, and this was possible by the plants and other bacteria that carried out the process of photosynthesis.
The increasing amount of oxygen gas resulted in the formation of iron in the ocean water, where some of the available oxygen reacted with the dissolved iron and gave rise to the insoluble iron oxide. These insoluble iron oxide then sank into the bottom of the sea floor and over a due course of time, it gave rise to the formation of the banded-ironstone formation rocks (BIFs).
The rocks in the terrestrial environment also reacted with the oxygen and after the process of oxidation, rusting of rocks took place.
Thus, the correct answer is option (A).