The concept of undermining by ‚Äö√Ñ√∂‚à ö√ë‚à ö‚â§foundation‚Äö√Ñ√∂‚à ö√ë‚à ö¬• was put forward by____________$

• A. F.F.Haigh
• B. Khosla
• C. Casagrande
• D. Pavlov sky