Correct option is C
A → III (Illite): Illite has K⁺ ions in the interlayer, making it non-expanding.
B → I (Vermiculite): Mg²⁺ ions are adsorbed between layers, giving it intermediate expansion.
C → IV (Chlorite): Has a characteristic brucite layer in addition to the 2:1 structure.
D → II (Smectite): Includes minerals like montmorillonite, which exhibit high swelling due to their expanding nature.