The correct answer is (d). All of the above.
The health of the soil depends on several factors such as the size of rock, which determines the water holding capacity of soil. The soil having smaller rock particles holds more water as compared to the soil having larger rock particles. The more the oxygen content of the soil, the better will be the growth of plants. The roots of the plants require oxygen for various functions. The moisture content enables the growth of healthy microorganism that is required for humification in the soil to increase the soil health.