The correct answer is d) All of the above.
Soil pH is a measure of the acidity or alkalinity of the soil. It is a scale from 0 to 14, with 7 being neutral. A pH below 7 is acidic, and a pH above 7 is alkaline.
Soil pH affects the availability of nutrients to plants. Nutrients are more available to plants when the soil pH is near neutral. When the soil pH is too acidic or too alkaline, some nutrients can become unavailable to plants.
Soil pH also affects microbial activity. Microbes are organisms that live in the soil and help to break down organic matter and release nutrients. Microbial activity is higher in soils with a neutral pH.
Soil pH also affects crop growth. Crops grow best in soils with a neutral pH. When the soil pH is too acidic or too alkaline, crop growth can be reduced.
Therefore, soil pH is an important factor influencing nutrient availability, microbial activity, and crop growth.