Given below are two statements, one is labelled as Assertion (A)... | Agrigyan

• Assertion (A) is True: Soils rich in smectite (montmorillonite) clays exhibit severe swelling upon wetting and massive shrinkage upon drying, forming wide, deep desiccation cracks characteristic of Vertisols.
• Reason (R) is True: Montmorillonite has an expandable $2:1$ layer crystal lattice with weak interlayer Van der Waals bonds and hydrated exchangeable cations that permit large volumes of polar water molecules to enter the interlayer spaces.
• Relationship: Because hydration of the expandable interlayer space pushes silica sheets apart to cause macroscopic swelling, Reason (R) directly explains Assertion (A).
• Conclusion: Both (A) and (R) are true and (R) is the correct explanation of (A) (Option 1).

Correct option: (1) Both (A) and (R) are true and (R) is the correct explanation of (A)