Cation exchange capacity of Kaolinite is

Correct option is C

Kaolinite is a 1:1 type clay mineral.
It has low surface area and minimal isomorphous substitution.
Hence its cation exchange capacity is very low.
CEC of kaolinite generally ranges from 3 to 15 cmol (p⁺) kg⁻¹.
It is lower than illite and much lower than montmorillonite.
Therefore option (c) is correct.