Answer: a. oxidation
Step-by-step explanation:
The weathering is a process through which the large rocks are broken into small rocks or pieces. The weathering can be caused by the physical and chemical agents.
The chemical weathering is a process in which the rock is disintegrated or broken into sub-components by the action of the chemical agents present in the surrounding of rock for example, air, water, acid, and alkali.
The air will cause the oxidation of the rocks. This will cause weathering of rocks as the oxygen will react with the minerals present in rocks making their bonds weak and causes disintegration of rocks.