Concept:Soil analysis involves testing the physical and chemical properties of a soil sample directly, such as acidity and particle size.
Explanation:A
pH meter is used to measure the acidity or alkalinity of soil, making it a genuine soil analysis tool.
A sieve is used to separate soil particles by size, helping to determine soil texture.
A hygrometer measures the relative humidity of the atmosphere, so it is not a direct tool used for soil analysis.
Therefore, among the given items, only I and II are correctly used in soil analysis.
Option III is not a standard soil analysis instrument.
Answer:A. I and II