Which one of the following has the highest cation exchange capacity (weight basis)?

✅Explanation:
-Cation Exchange Capacity (CEC): CEC is the ability of a soil to hold and exchange positively charged ions (cations) like calcium, magnesium, and potassium, which are essential plant nutrients.
-Humus & CEC: Humus, the decomposed organic matter in soil, has a very high CEC due to its numerous negative charges. These charges attract and hold cations, making them available for plant uptake

📌 Other Options Explanations:
-Option A: Kaolinite
-Kaolinite is a 1:1 clay mineral with a low CEC due to its limited surface area and charge.
-Option B: Illite
-Illite is a 2:1 clay mineral with a moderate CEC
-Option C: Montmorillonite
-Montmorillonite is a 2:1 clay mineral with a high CEC due to its expansive structure and large surface area