What is the major source of minerals in the soil?

The correct answer is: "Parent rock from which soil is formed."

Minerals are produced from rock i.e. parent material.

Weathering of rock is a process that forms soil. The parent material can be broken down with the help of living things, water, pressure, temperature fluctuations, gravity, and wind. Decomposers can help restock the organic matter and minerals in the soil.

Hence, rock is the source of minerals in the soil.